I See Me Books

I put in two separate orders on 12/1/13 with ISEEME books. Within a day, both credits showed up for the orders. (two orders, two separate order numbers) I noticed today one of the orders shows now CORRECTION after it and the credit is now $0. Are you not able to get credit for two different orders with the same merchant on the same day? It wasn't my intent to do two separate orders but shortly after I placed the first order, I decided to order another book for a gift. I'm not sure if I should put a trouble ticket in for the credit or if there is a specific reason that one of the credits was corrected to $0.