RS Gamecard Help?

I bought a few 90-day cards in order to sell them for RSGP about a week ago. I just found a buyer, but when he tried to apply the first upgrade it said that a problem occurred while trying to apply. Correct country was selected, and I have a picture confirming that the error message actually appeared. Does anyone know what's going on, and how to solve this problem safely for all parties?

 

Two reasons errors happen here.
1) Card was entered incorrectly, double check it.
2) Jagexs' system goes down every now and then for no reason. So keep trying every 10-15 minutes until it works.
3) Card was already used by someone else (doubt it)

Experience: Owner of www.memberize.me

 

Well, what could have happened. Is when you gave him the code to apply, he applied it once, it worked, and then he re-input the code and he got that error message and could have scammed you.

that's a pessimistic way to look at it.

A more optimistic way of looking at it, is maybe the card wasn't properly swiped by the store that you purchased it from.