I can't make or receive calls on my phone. First it said my sim was in nvalid then all of a sudden it says I haven't Sim card installed? I reset the phone then it went back to normal on everything except calling. My boyfriend and I both access my phone and I don't know if this is a system error or possibly foulplay? There has been some wierd things happening that he denies? Any input would be appreciated. I hope it's just my phone but I have no other way to call customer service so any ideas would be helpful. Thanks