Issues with Dropped phone calls

I have new Motorola backflip phone with Android OS 1.5 Model MB300

It keeps dropping phone calls al the time. I took my phone to the store and they replaced my SIM card. Also, I did a factory reset already 3 times and whipped all my data.. Still my phone keeps dropping phone calls. BTW, I am in NYC and not outside the area. I just got a replacement device from ATT. And, the problem is still there. My phone lost connection 5 times today….More over I get this prompt “android.com application stopped working” and it forces my phone to close..

I don’t know what to do. ATT service is terrible.