Very unhappy!!

I unfortunately am not happy with SMG BMW Century City. I have never expected poor service from Bmw. I am shocked and very unhappy with them. It is a 118i F21 AT

My Bmw was booked in 3 months ago for drivetrain malfunction. So they ordered brand new fuel injector from Germany. I took 3 weeks for it to arrive and the car was already there for 1 week so it took 1 month and i got my bmw back. I had the car for a day and same problem again, the bmw went back to them and now 2 months later the bmw is still there and i still don't have my car. A total of 3 months now at SMG and i am not happy with this. I keep on popping in every Friday but I don't really see or hear anything from SMG. They say they will call me back and they will keep me updated but unfortunately they are absolutely useless!! I need my car back asap!!

I am paying monthly for my car at the moment and i don't have my car at all. 3 Months total so far!!!!