[HLHachiRoku]

If the car was working fine and driving fine before it was dropped off, it should drive right out of there. Shop is responsible for the car while its on their property, its why they have insurance. If it won't drive off/start whatever they are liable.

2 things: 1) battery is drained, usually batteries don't drain THAT fast on a tint job unless the morons leave the keys in/lights on/drls on etc... tint doesn't take all day, 3hrs max, or less for this car. The car can have 50 v, but not enough cranking amps to turn the starter over. I'd change out battery 1st, if they are trying to check the ecu with a faulty/dead/dying battery it will give them all sorts of bad numbers... whoever is working on the car should have checked the battery 1st... what morons.
2) Someone there jacked your ecu and did a switch. plain and simple. doesn't matter if you saw a 86 there or not. If someone worked there/had a friend and bricked their ecu like others have said, they could have moved it out of camera site or at an angle you wouldn't beable to see what they are doing.

Why was the door open and they were pushing it?! Seems like maybe it wouldn't start for them? or they changed out the ecu and couldn't get it to start to move it, so made it look like it was moving on its own?

I dunno i don't trust anyone to work on my car anymore after my bad experience when i was 18, long time ago, lol. To many con artist/rip off people/morons that people hire that don't know jack and ruin your car. Why i learned to do all my own work, engine, transmission etc rebuilds. lol. I hope your car gets fixed and up and running again =D and its a simple battery fix. =D