I have the same phone which I purchased 2 months ago. You are absolutely right. It doesn't matter where, calls just keep dropping. I trying to get T-mobile to replace the phone for me but they want me to pay for the other phone. It is a really a bogus phone. The unfortunate part is that my husband and me have the same phone and we are only two months into our one year contract.
I purchased a Moto V300 (T-mobile) a couple months back and suddenly my calls are all starting to drop after a few minutes regardless of where I am at. I have always had excellent service from T-Mo in my area and tried my hubby's Nokia 3390 (also T-Mobile)this weekend and it worked great. When I phoned T-Mobile about this they stated that I may need a new SIM card. (The SIM I have in the new phone is from an old phone I had). Could this be possible? Also, many of the dropped calls I am receiving are in my home that has a WLAN. Could this just be my WLAN's radio signals interfering with the V300 since it is a web enabled phone? As a test, I did shut down my WLAN and still received dropped calls though...Can anyone assist?