1993 Honda Civic No Cruise Control, Wont get out of park, a

Was hoping someone could shed some light on my situation with my car, 1993 honda civic lx. I picked it up from the shop on Friday, having the distibutor and ecu replaced. When I picked up the car it started up nice but wouldnt go out of "park", I had to put the key in hole on the shifter to start the car in neutral then put it in gear. After driving the car 15 minutes the "check engine" light comes on, and my cruise control now doesnt work. I brought the car back yesterday and told the mechanic all the new problems Im having now. He said that the car had done all of that for him and his main concern was just getting the car running. He said that to save money he had put in an ecu from a DX and my car is an LX. I was hoping someone could shed light on whether the DX uses a different ecu then an LX? And if putting in a different model would cause the problems im now having? The computer he said he took out of my car is 37820-p06-a51, and he said he put in an a52, dont know why he thought itd be ok. I feel like these guys are jerking me around and I need to know whats really up so I can argue with them. This has been a nightmare dealing with these guys and im never going back. Just trying to get this done and over. Id like to thank you very much for any and all info you can give on this, definately appreciate the help. Thanks a ton.