Airtel — no service in usa.

I am using samsung galaxy pop. My airtel no: [protected]

And for last 6-9 months no network here in usa. It simply says no sim and does not even work. It used to work in the same phone before and through at&t network. Now when i refresh for networks, it simply shows t-mobile and does not even list at&t. I have international roaming pack activated and been paying bills without miss. And still no service.

I have complained through phone calls and twitter messages but no help so far.

One of my friend also suggesting the same issue for him and it would be great if you could reach me at my usa number +[protected] to resolve this issue.