UKPassats

I have a passat with bkp injectors with a 23h9 seal, however and according to the mecahnic ,and due to some ignition problems, and according to a strange flow rate , he replace the orings, clean and did a calibration, after that they were good about 2 / 3 months with normal flow rates, however now the mechanic says that injector 4 is with high values ​​(1-1.20) and that it is possibly the electrical part to die, but from what I have seen on the internet when the that part has a problem the car stops, does not change the debit values! I think that the maintenance they did may not have been well done and as I have a guarantee I can complain.

its important to say that the start issues remains since 2017, and as i put here in another post, it only happens 1 or 2 times per month, i need to press the key 6/7 second to start the engine, after that all normal, running normal.

in your opinions what should i do??