RP code not working

On Christmas 2014, I received 2 rp gift cards. My first $10 gift card went through fine, but then i tried to use my second $25 gift card. It said http invalid or something like that and it didnt work all night. The next day, i tried again and it said the code was already used. I tried everyday after that and it never worked. I know for a fact that no one has the code, and i am putting in the code correctly. Because of this, i know for a fact that the fault is on riot.