Hi and welcome to iMore. This is primarily an Apple site catering to iPhones, iPods, Macs and other Apple devices. We have a sister site called Android Central over at -
Android Central | Android Forums, News, Reviews, Help and Android Wallpapers - and they may be able to help you further.
Saying that, a number of us here also have Android devices, myself included. If I understand you, you are saying that Straight Talk deactivated your phone. Do you mean that no SIM cards will work in the S2 at all, or do you mean that they deactivated your SIM card only? if they deactivated your phone, do you know why? Surely this isn't allowed, it certainly wouldn't be over here in the UK anyway.