And to prove that they are aware of the situation , just complaint more than once and they admit to their faults and even offer you a 200$ credit as an incentive to buy you off and push you onto the 3G network. The 2G network is used by a lot of handsets including Blackberry, RAZR and the original iPhone with loads of users. The trouble originates because both the networks require seperate transmitters. In a bid to cut costs, AT&T is instead simply replacing the 2G transmitters with 3G ones.

AT&T customers who are on the 2G network are now reporting low network ranges in areas that were previously trouble free. While one could possibly understand this if it AT&T had announced that they were going to shut off the 2G networks slowly (which it obviously cant) ; AT&T continues to sell 2G handsets without informing the customers about the network issues.

When complained to, they simply offer the aforementioned credit along with a request to upgrade to the newer network.

Source