Have a read here, i went through all the processes one-by-one. From easiest/most common to hardest/lengthiest; AT&T Bold, Os 5.0/Data/Sim Malfunctions!
Good luck and post back if there was anything useful to you there that helped solve the issues.
Originally Posted by snoo
You bought it off ebay - maybe its stolen and has been banned by the carriers?
I Googled for "checkmend" which is a stolen IMEI database, but I've never used it before. It only cost a couple of dollars/pounds - maybe someone else can comment on this before wasting your money?
That program is aimed at 'new' handsets. If it was in fact previously used on an old account, [lets assume stolen in this case], its beyond the carriers hands to 'fry the sim slot' per say. If it was a brand new - never activated device than this is what the program is for... but anyways this is a rather common issue i have personally experience on one of my 20+ bb's in the past.