well if you know the number, you can call t-mobile and tell them you don't want to receive calls from a specific number. if it's blocked you can try to tell t-mobile you dont want blocked calls calling you
I dunno if this still works but I had the Cellular Do Not Call # as 888-382-1222 I had registered some time ago and haven't received any solicitations at all. Might try it.
Posted from my CrackBerry at wapforums.crackberry.com