When I first got my phone I threw in my sim from my iphone on ATT and it worked great. Just like it should. Then I moved to the everything unlimited plan with t-mobile a few days later and now I have crappy service and people are constantly complaining of calling me and my phone just rings endlessly with no hope of a voicemail, but their calls never come through to my phone. However the calls that do come through If I don't answer them they are forwarded straight to my voicemail and everything works as it should. What could cause the calls to get lost in oblivion, I would say 30-40%. Is t-mobile just that bad?