AAMCO Scam

Hello,
I took my 2002 Explorer to AAMCO for a transmission fluid change on 2-18-09. Soon afterward, I found the transmission would disengage on a hard stop. I took the car back on 4-22-09 to check on what the problem may be, and AAMCO Customer Service Manager David Migdol told me to come back later in the afternoon. As my free time is extremely limited, I took the car to another certified repair shop, and they found the transmission fluid to be 2 quarts low!!! How can that be? My car does not leak a drop of anything. After paying $48.64 for the solution to the problem (the car runs great now) I went back to Mr. Migdol, and I was practically accused of lying. He told me he would give me an unspecified discount on some other service, but I do not trust AAMCO to do a proper job anymore. What is my recourse for reimbursement of the $48.64 spent on repairing my car correctly? Who knows what damage was done to my transmission after driving two months with low fluid. I am quite upset and disappointed. AAMCO never again.