Bluetooth won't stay connected

Why is my Plantronic's Headset not staying connected?? I can be on a call using my headset and a call waiting call come in... disconnect from the first call to switch over and the headset disconnects. It will not reconnect unless I turn off bluetooth on the phone, then restart. Even then sometimes I have to turn the headset off and back on. From one call to the next on a $1,000 phone seems ridiculous!! I've tried this with an older bluetooth headset as well, with the same results.