Okay so my mom recently got me a iPhone 3GS and it is Unlocked and jailbroken from the previous owner because they had T-Mobile too for this phone and I put a new SIM card in it and I did all the steps to activate it and it's activated on the $30 prepaid monthly 4G plan (includes Unlimited text, web, data + 100 mins talk) and when I tried to make a call to the voicemail it said "Your cell phone carrier does not allow you to make calls to this number" and I've tried various other numbers and the same message comes up. So I thought may its a call limit and I tried to text and it failed. It has the T-mobile thing at the top where AT&T should be and it says it has bars and it's in EDGE mode(plus every 5 seconds it loses service). I've tried messing with the settings to make it work but nothing happened. PLEASE HELP!!!