[William Saldarriaga]

I need help. 80% of the time I try to call someone and I can't. For example when I call a friend my phone doesn't ring its just silent and then after a few seconds I hear one beep and then the call ends. With messaging too, I try to send a message and it says "Message not sent". I've gotten my SD card changed by T-mobile when I wanted to solve the problem but its still not working.

[B. Diddy]

Welcome to Android Central! Have you spoken further with T-Mobile after trying the new SIM card? Is your cell signal good when the calls drop? T-Mobile doesn't always have the best coverage, depending on where you are--especially if you're indoors.

[Gustavo Fernandez]

I need help. 80% of the time I try to call someone and I can't. For example when I call a friend my phone doesn't ring its just silent and then after a few seconds I hear one beep and then the call ends. With messaging too, I try to send a message and it says "Message not sent". I've gotten my SD card changed by T-mobile when I wanted to solve the problem but its still not working.

I have the exact same problem with my unlocked AT&T S3 which I am trying to use with TMobil. In case it helps, I did upgrade to 4.4.2 kit Kat before canceling the at&t service. I have already tried hard factory reset and new SIM. The sim works with a different phone so I don't think that's the problem. Any help will be appreciated!