Engine shut off while driving

I had the PCM replaced in January, I don’t suspect that it was not done correctly, since then the auto light function, the wipers (auto) and the CD player have been malfunctioning. The other day it completely shut off while doing about 30 mph. I had it returned to the same dealership, convinced that it was PCM related. Now they are telling me that it is not a PCM issue but that my ignition coils are bad and that they will all need to be replaced at $250.00 per coil. I strongly suspect that they are trying to milk me out of another $1,200 .00 and that they are trying to cover for their poor installation of the PCM module. My car showed none of the symptoms of ignition coil failure. I feel very taken advantage of and suspicious of the dealership since I take very good care of my vehicle and have had zero problems before they put in the PCM. help please!