Airtel Prepaid — Sim not working

This is to inform you that I have taken a prepaid card no ( [protected] ) .in december 2006 . From last 2 months I am facing problem like no network on my handset as using Sony K 700i as Iface this problem in a day 2 to 3 times
Visited connect and check the sim on doctor sim & changed the hanset to Nokia but still this problem persues.My name is also been mismatch from the Airtel backend as when taken the sim on my name Firoz Peerzade but now is is showing as some Shah so why is this problem kindly help me to resolve this problem.
Connect people are telling me to change the no which is not possible for me as I am your postpaid very old customer My No ([protected]) So hope that youn can help me with the same No