An issuing bank will ask for a retrieval (or request for copy) from a merchant after a cardholder contacts the bank to dispute a charge. Retrieval requests can be made by issuing banks up to 18 months after the transaction. Upon being notified of the request, merchants must provide all relevant records of the sale, Failure to respond to retrieval may result in the retrieval becoming and chargeback and for some processor may make them ineligible to representment if/when a chargeback is issued.*
*https://www.merchantconnect.com/CWRWeb/retrievalfaq.do