Transmission R and R

I do not recommend this business at all. Had a transmission R&R. It has been back in several times due to the transmission failing and not working after the original R&R. The first time it failed within their 6 month warranty. They take a week to do any work, said it was ready the second time when it wasn't due to a substitute part that didn't fit properly and caused severe shuttering so I wasted a trip then had to leave it again. They have not once put the proper amount of transmission fluid in. The first time I brought it home the transmission fluid was seriously overfilled by 2 quarts and they said that was just fine and wouldn't hurt it but all of the online mechanical advice states the opposite that it can damage and /or destroy a transmission. The day after picking it up for the third time it started shuttering again and upon checking the fluid it was underfilled by 2 quarts. The last time they had my car they had it for a month and still did not manage to fill the fluid to the correct level.