Did you try deleting the connection from both the phone and the car, and then repairing them? That might work. Mine works great now that I got the software upgrade. I have the Razr from Verizon, though. Maybe you should go back and get one of them. I love the phone.
2008 Sparkling Graphite 535i
2009 Land Rover LR2
2003 Porsche 911 Turbo (SOLD)
2006 Jet Black 325i (SOLD)
2001 Bullitt Mustang (450rwhp - SOLD)