You're lucky they could find the problem - and then fix it.
Key & timing chain? Don't know about timing chains having "keys".
Please ask again and see if it was the key in the key-way holding the rotor in place on the shaft. That would have a lot to do with the timing and it not starting or running. The timing sensor pickup works off this area at the rear of the rotor. Seems to be a similar problem that has been cropping up enough to have 'some' dealers checking this area with symptoms like this.
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