How do banks and credit unions investigate disputes on debit cards?

The card-issuing bank or credit union is responsible for reviewing the transaction data and evaluating whether a customer's claim of fraud has any validity to it. The bank or credit union may contact the merchant and ask for proof that the debit card customer permitted the charge.

The process can be time-consuming, but this extra bit of investigation will help ensure that only legitimate retailers are compensated by their banks or credit unions. If it is clear that the dispute is valid, then your debit card will be refunded appropriately.