Billing disputes between agents

A billing dispute starts with a charge the person does not recognize, did not authorize, or paid for without getting what was promised. There are two separate paths. One goes to the merchant, which can refund. The other goes to the card issuer, which investigates under consumer credit rules and can pull the money back through the card network. A person’s agent could work both paths directly with the other side’s agent, with a record neither side can rewrite.

How it works today

The merchant path. The person searches their email for the order, finds the merchant’s support page, and asks for a refund by chat, form or phone. Many “disputes” end here once the person recognizes a billing descriptor.

The issuer path. The person taps “dispute” in the card app or calls the issuer, answers questions, and may receive a provisional credit. The issuer files the case through the network. Visa’s dispute guidelines for merchants organize cases into numbered dispute conditions with a time limit on every step. Mastercard’s Chargebacks Made Simple guide describes chargebacks and compliance cases exchanged between issuer and acquirer, with fixed windows for each response and appeal. The merchant answers with evidence, and the case can escalate to arbitration.

US rules for credit cards. Regulation Z section 1026.13 implements the Fair Credit Billing Act. Its protections attach to a written notice that the creditor receives within 60 days after sending the first statement showing the error, at the address it designates for billing errors. The creditor must acknowledge in writing within 30 days and resolve the error within two complete billing cycles, and never more than 90 days. While the dispute is open, it may not try to collect the disputed amount, report it as delinquent, or close the account only because the consumer disputed. Section 1026.12(b) caps a cardholder’s liability for unauthorized use at $50. Section 1026.12(c) lets a cardholder raise quality disputes against the issuer, but only above $50 and, in most cases, for purchases in the cardholder’s state or within 100 miles of their address.

US rules for debit cards. Regulation E section 1005.11 accepts oral or written notice within 60 days of the statement. The institution has 10 business days to investigate, or it can take up to 45 days if it provisionally credits the account within those 10 days, with longer windows for point-of-sale debit transactions and new accounts. Section 1005.6 limits liability for a lost or stolen card to $50 if the consumer reports within two business days of learning of it, and up to $500 after that.

Canada. Card dispute rights sit in provincial consumer law and the networks’ own rules. Ontario’s Consumer Protection Act, 2002 (s. 99) lets a consumer who cancelled under the Act and did not get a refund ask the card issuer to reverse the charge. The request must be in writing, and O. Reg. 17/05 (s. 85) requires the issuer to acknowledge within 30 days and act by the second statement after the request. Quebec’s Consumer Protection Act lets a consumer request a chargeback within 60 days of a merchant’s refund default (s. 54.14). The issuer must acknowledge within 30 days and complete the chargeback within 90 days or two complete periods, whichever comes first (s. 54.16). Federally, the Financial Consumer Protection Framework, in force since June 30, 2022, gives banks 56 days to deal with a complaint before it can go to the Ombudsman for Banking Services and Investments.

The agent-to-agent version

Illustrative. The person’s agent tries the merchant first, then the issuer.

1. The agent sends the merchant’s agent the descriptor, amount and date, and asks what the charge was for.
2. The merchant’s agent matches the charge and returns the order, or states it has no matching order.
3. If the charge is the merchant’s and it refuses a refund, the agent files with the issuer’s agent, attaching the merchant’s answer.

The issuer-side request carries the fields Regulation Z names for a billing error notice: the account, the amount, and the reason the person believes it is wrong.

{
  "jsonrpc": "2.0",
  "id": "req-dsp-1",
  "method": "SendMessage",
  "params": {
    "message": {
      "messageId": "msg-dsp-01",
      "role": "ROLE_USER",
      "parts": [
        { "text": "Billing error notice for one charge on the September statement." },
        {
          "data": {
            "accountRef": "card-token-4c1e",
            "statementDate": "2026-09-05",
            "transactionId": "txn-55821",
            "amount": { "value": "189.00", "currency": "USD" },
            "reason": "goods_not_received",
            "merchantContacted": true
          },
          "mediaType": "application/json"
        },
        {
          "url": "https://agent.example/evidence/txn-55821-merchant-reply.pdf",
          "filename": "merchant-reply.pdf",
          "mediaType": "application/pdf"
        }
      ]
    }
  }
}

The issuer’s agent replies with a task that records when the notice arrived and what happens next. That timestamp starts every clock in the regulation.

{
  "jsonrpc": "2.0",
  "id": "req-dsp-1",
  "result": {
    "task": {
      "id": "task-dsp-903",
      "contextId": "ctx-dsp-11",
      "status": {
        "state": "TASK_STATE_WORKING",
        "timestamp": "2026-09-26T14:12:09Z"
      },
      "artifacts": [
        {
          "artifactId": "ack-dsp-903",
          "name": "Dispute acknowledgment",
          "parts": [
            {
              "data": {
                "caseId": "D-2026-903",
                "receivedAt": "2026-09-26T14:12:09Z",
                "disputedAmountSuspended": true,
                "provisionalCredit": false
              },
              "mediaType": "application/json"
            }
          ]
        }
      ]
    }
  }
}

What has to be true

Identity. The issuer must authenticate the cardholder behind the agent, and know which agent it is dealing with. A card token or account reference replaces the full card number in the message.

Authority. A dispute is a claim the cardholder makes. The issuer needs evidence that the cardholder authorized this dispute on these transactions, and nothing broader. A credential scoped to “dispute transactions X and Y” should not let the agent change the mailing address or request a new card.

Written notice. Regulation Z’s protections depend on a written notice at an address the creditor designates. Whether a structured message to an endpoint the issuer designates meets that requirement is for the issuer and its regulator to decide. An issuer that accepts disputes this way would need to say so.

Record. The 60-day, 30-day and 90-day windows are all measured from dates. Both sides need a timestamped, tamper-evident record of what was sent, when it arrived, and what evidence was attached.

Where Emissar fits

• Front Door (open to design partners): lets a merchant answer “what is this charge?” for agents before it becomes a dispute.
• Verify (in development): checks the calling agent before the issuer or merchant acts.
• Mandate (spec in progress): proof the cardholder authorized a dispute on specific transactions.
• Ledger (spec in progress): a signed receipt of the notice and its arrival time, retrievable by both sides.
• Handoff (in development): contested cases and fraud claims go to a person with the full exchange attached.

Open questions

• Will issuers designate an agent endpoint as a valid address for billing error notices?
• Card networks define evidence formats for merchants. Would they accept evidence assembled by agents, and in what form?
• Agents make disputes cheap to file. What limits keep automated filing from overwhelming merchants and issuers without blocking valid claims?
• A cardholder may dispute a charge their own agent made. How should an issuer weigh a dispute when the purchase itself was agent-initiated under a payment mandate?