Cant credit an Item using my card!!!!

I have an account with Ackermans, so today I went to the Ackermans Liberty Mall to credit something that I had bought on account 2 weeks ago. I misplaced the slip so I assumed since I bought it on account they will be able to pick up the transaction using my card since it was done this month... Guess what They can't apparently their system doesn't do that... Such ******* what kind of shop doesn't allow a customer to credit something on their account... Shops are able to track your transactions in your card using your purchase history.. I am sitting with a pair of boots that I can't return cause I misplaced a slip... ****ed!!!