gift card drama......

I received five gift cards to my favorite store for Christmas! I was so excited, I had them all neatly hidden in my billfold. Last Friday night Caroline and I decided to go to the mall so I could use them, and purchase some perfume I have been dreaming about.......I get to the check out, and pass my gift cards over to the check-out girl.......she slides my gift card through the slider thingy.......she says "I am sorry, this card has not been activated" WHAT, "this card has not been activated"...I almost started to tear up........now what do I do......"do you have the receipt".....no it was a gift........well......."you really need to find the receipt" , it was a gift, I do not have the receipt...soooorrrrryyyyyy maaammmmm . So now what do I do??????????