I think this will be a hard one to solve, I have tried my best to change my phone number on steam, the only way I can do it (it seems) is they send me an SMS to my phone number (thats registered already) but I dont have access to it anymore (Virgin ported it away from me for some unknown reason and cant recover it again) its almost impossible to contact them by email or phone, and I dont know if its possible to do it, thanks