If the merchant and issuer each insist the other side is responsible, send one written case containing the original transaction, refund date, ARN or trace reference, issuer ticket and the statement showing no credit. Ask the issuer to confirm the trace result in writing.
If the refund remains unresolved after the issuer’s internal grievance process, use the current complaint route that applies to the regulated card issuer. Keep the merchant dispute separate if the merchant never actually initiated the refund.
Do not close the case because a support agent says “wait seven more days” without a new trace result. A useful escalation should identify where the money is in the payment chain and what exact action is required to post or return it.