Ok, first things first, explanation. My brother, whom for the purposes of this text, we shall call jim, now jim bought a 360 and kindly said I could have the month free xbox live to use on my pre-exisiting account. Sounds nice, apparently not. The box didn't come with a month card instead, I gather it's one of those built into the console things that activate when you make an account, now has anyone managed to use their 360 slim month on an existing account or knows how to, thanks 
Wall o text summary: Use free month on existing account
Wall o text summary: Use free month on existing account