Motorola V360 / V361

Can anyone help me?? I have a Motorola V360 with T-mobile service. It's a new phone. When I plug in the phone to charge, it goes silent and does not ring when someone calls me or when the alarm is set to ring. I checked the ring style and it's set to "loud" and the volume is turned up all the way. I changed the ring style while the phone is plugged in charging and it doesn't matter- still no sound. I performed a "Master Reset" on the phone. I called T-mobile and they sent me a new phone. I called Motorola and they offered no help either. What is going on?? Is this phone just stupid and it doesn't ring when being charged or am I the stupid one and I can't figure out the settings? If you have this phone and the same problem please contact me!