iPhone 4...4.3.3. Modem firmware 3.10.1 NO SERVICE issue...NEED Assistance ASAP!!

[applelover89]

Just recently got an iphone 4, jailbroken 4.3.3., issue is the phone doesn't receive any service whatsever. Got a new micro sim from at&t and still nothing. It shows one bar but under general > about > network = unavailable, carrier = not available...any help or suggestions??!!