Apologies if this is posted in the wrong place.
I have a 2012 fiat 500 twin air street with 33k miles on it.
Serviced regurlarly .
A month ago the twinAir unit was replaced at £1000
Had it serviced two weeks ago and everything fine for a week. Parked it and left it for a week then went to start it - the generic fault light and the padlock light came on the dashboard and nothing happened. Lights, battery etc all ok. The car seemed to be immobilised so it was towed to Fiat. Neither key was recognised
Fiat say the injector ECU has failed and it will cost £1000 for the part!! I find it odd that the ECU would just die without warning.

I have people telling me it is the transponder and to get it recoded , who to believe?

Any one had similar experience or I am having real bad luck with this car?