iPhone 4S suddenly stopped working with Bluetooth hands free device even though it says they are paired and connected

My iPhone 4S suddenly stopped working with the Bluetooth hands free device I’ve been using for months (Motorola T215) with the same phone. The iPhone pairs with the device and says they are connected but I can't send/receive calls or use Siri through it anymore. Incoming calls don't ring through the Bluetooth device and when I press the main button on the hands free device Siri doesn't come through. I tried deleting the device and re-pairing it with the iPhone but this hasn't fixed it. The device is fully charged and appears to be functioning. Everything was working fine until Friday, 10-Aug-2012. Any help or advice would be greatly appreciated.

Thanks,

Mel 😕