Game codes confusion.

Kuji-Kiri

I'm asking the WAR players for a little help here. My friend just got his CE codes, but he seems to be confused about something. He says his doesn't work. I offer to try for him, and I get in his account and input the code, select payment plan (pre-paid gamecard), and I find out that he's putting the CE code in the pre-paid game card section instead. I tell him this and he says that he should be able to play the free month without paying for anything or doing anything like this (he says it was like this in WoW). I told him he has to either use a credit card or gamecard first if he wants his free month, but he won't listen to me. Now, maybe I'm the wrong one here, but can anyone give a step by step processes, because I need someone else to help me help him see what to do.