It sounds like the transmission shop you paid $700 to is quite a shady operation. However, I wouldn't start with the Better Business Bureau. Transmission repair shops are usually licensed by the state in which they operate. I would start by calling your state Attorney General. The AG office of several states, mine included, has an Automotive Fraud Division, and they love to get complaints like this. The AFD of our AG office (Michigan) conducts periodic stings of auto repair shops, and transmission repair shops are the ones most frequently charged with violating the law.

1977 CJ-7, fiberglass body, AMC 360 w/ headers, DUI ignition, Edelbrock intake and Holley 4150 carb, TF999, Dana 300, 4.56 gears lockers, York air comp, 4" susp lift, 2" body lift, BFG 35" M-T tires, Megashifter, AGR pump & box, REP8000 winch.