2001 Chrysler PT Cruiser wont start

I have had the head gasket and timing belt and water pump replaced on my pt cruiser, it then would not fire the mechanic replaced the cam and crank sensor and still no fire, he then wanted to replace the coil pack and instead towed it to the dealer who informed him it had a bad ecm. My question is it something he could have hooked up wrong and it is giving a fault bad ecm code instead, I find it hard to beleive that all these parts and throwing more parts t the vehicle and now the ecm is bad, he said the battery was dead and he had to charge it to try and crank it, the vehicle turns over but no fire, I asked if he tried resetting the key and he said yes but acted like he didn't understand what I was talking about. I am not sure if the guy was qualified to put it back together and may have screwed up something, I asked 3 times if he double checked the timing marks when he installed the belt and and he said yes