Can not exchange a gift received

My sister purchased a set of 4 cognac glasses for me as a gift from the @Home store in Zevenwacht mall on her Foschini account. I asked if I can exchange it for the red wine glasses and she gave me the receipt. I went back to the exact same store, but was told that I needed to be the account holder to do an exchange. Firstly the shop assistant already stamped my receipt \returned"and then another shop assistant says that I cant even exchange it. Secondly"