First off, a bit of back story. Earlier this year (Or late last year, the date itself is irrelevant) The Xbox Live account I'm currently posting from was hacked. The hackers managed to spend £50 on my account which was not refunded by Microsoft as apparently there was not enough evidence regarding the matter. I let that slide as I can see where they are coming from and bolstered my account security.
Fast-forward to now, I just bought the Age of Empires Online DLC via Steam but had an issue regarding the product key and after searching various forums discovered that the only way to fix this was to download the Games for Windows Live version of the game (Which is another problem in itself). Problem is, despite being free, whenever I try to 'purchase' the game it brings up a message saying a code has been sent to a phone number. I can only assume this number is that of the aforementioned hackers.
I have no idea how to change this number or get around this problem at all bar creating a new account, which is way too much hassle. So long story short is there any way of changing this number? Or has Microsoft screwed me yet again?