Yesterday my Razr M started dropping calls when I'm calling from places where I normally use the phone and have not had problems. I will be talking then I hear a beep and the call is gone. This is very annoying to say the least. As I said two days ago it was fine and suddenly yesterday and today it is doing this.
Mine has been dropping calls the entire time I've owned it. I'm not happy. I had two different Blackberry's that never dropped calls. But once I swapped over, it happens all of the time.
Could be tower issues in the area or your SIM card. You might try turning off the phone, removing the SIM card, waiting a few minutes, then reinserting the SIM card, powering the phone back on, and giving it time to re-establish a connection to the network. Sometimes a new SIM card is needed.