Hi, I'm having a problem with my S2 (SHW-250K). I'm able to receive sms but not able to send it. It says "message not sent" and theres a red exclamation mark next to it. I've tried resetting the phone to factory setting and hard resetting it mutiple times but after all that it still doesn't send. I switched my sim to another phone and im able to send it with that phone. can anyone help?