Nokia 6126 problem

I just tried replacing my Nokia 6340i with a Nokia 6126 flip quad band GSM
phone. Everything I read about it looked good. However, it did not take long
to realize my voice was breaking up at the far end, while I was not having
any problem on the receiving end. I thought it might be due to a weak
signal, so I drove to an area in my neighborhood that had a very good
signal. I had the same problem. I called the cingular dealer where I bought
it, (about 15 miles away) and he said to bring it back for a replacement.
Before turning it in, I tried it at the store, and it worked fine. I brought
the second phone home, and had the same problem. After trying different
locations within 5 miles of my house, I found some areas that never worked
correctly as well as areas that had no problem. The signal strength did not
seem to be a factor. I called AT&T support to see if they could offer any
suggestions. They said I was the only one reporting this problem, so they
would not open a service order on it. I finally returned my new 6126, and
went back to my old 6340i. I don't know what to do next. The problem seems
to be a tower configuration that has a problem with a quad band GSM phone in
some areas. I have had cingular as a carrier for many years, but may have to
go to Verizon to get away from this problem. Does anyone have any words of
wisdom of what I should do next? I have not tried any other model phones on
the AT&T network. Charles Ranheim