MyTouch 3G call waiting issue

So I have been on 3 networks and 4 phones over the last month. I am currently using the mysuck 3g.

If I'm on bluetooth in the car on a call and get a second call, I get no indication of a second call. It shows on the screen, but no beep, vibrate notta. Add the major lag that the phone has and you don't even get the indicator on the phone if you are navigating.

If I have the handset to my head I get a very low beep. Just one. They only way I could even hear it was if I was expecting it and ceased all conversation.

IMO, this is a major flaw and after hours on the phone with the people at T-mobile they, admitted it. I have missed way to many important calls to keep this phone.

I asked if the Behold II has he same problem and their support people don't even have one to support people.
It's pretty sad.