No communication for programming TCM

Purchased used. Car ran fine, had the oil changed and cab+engine filters. Within a few days check engine light came on. The instrument panel started acting up, the transmission shifted harder then usual and the A/C would stop blowing cold. This persisted and would go back and forth with the Instrument panel and cold air.
Went to AutoZone to have the codes ran. It came back pointing to the TCM. The guy pulled up the part and told me I would save money using the old one as a core charge.
I went home watched some videos did some research and clearly found incidents where it was related to the symptoms I was having.
I purchased the new TCM and installed It. I had no idea that it needed programming/flashing. The car will now not shift. Seems stuck in 1st or 2nd.
I hired a guy to come out to my house to program it. He pays for the program and after some time he tells me in a nutshell that he can't program the TCM because there's no communication. Several things are not communicating and he shows me what's communicating and what's not. He asks if I have the old TCM which I don't. He suggests to try to get my core back which I can't. He then says to get another TCM as it's under warranty. He then will then come back out and check again. He suggests that it's the wiring harness possibly and that I will have to resolve the issue before he can program the TCM. He said he paid for the software already and charged me $100.00 and it will be another $100.00 to finish the job. Please any help would be appreciated I will be as responsive as possible.