I've always received a credit from AirTran when my fares have dropped. It is a credit toward a future flight that's good for 1 year from the ORIGINAL booking date. Not a credit back to your credit card. You can do this only one time per flight. This is the first time I've heard of someone being charged a change fee.

The only thing I can think of is that possibly you have to be an A+ Rewards member???? They've never said anything to me about it, but my member number is on the reservation. I sure hope they haven't changed their policy!!