Repairs taking forever after car returned to CMC

We purchased a vehicle bmw 323i Exclusive M Sport 2007 from CMC Lifestyle on 14/03/2015 and a few days later took the car to our bmw mechanic Noor BMW in Wetton where he tested the car at our expense and advised that the differential will need to be replaced as we reported that car made a strange noise.We then took the car back to CMC and advised them of our findings where they sent the car to their preferred mechanic Baboo who took a week and a half to replace the brake clamp missing on the driver's side back wheel,he would then drive the car to hear if that fixed the noise but it did not.Gearbox Exchange did the differential.Their mechanic then had to also replace the bulb for the Xenon light as well but this is where the whole messup occurred.He replaced the Xenon light but breaking the clips on the back and also not fitting the part correctly as when they washed the car at CMC the light misted up showing a leakage.The error came up on the board reflecting that something wasnt right with the Xenon light.We took it back to Noor advised the controller unit needed to be replaced and the light needed to be coded.We took the car back but after endless up&amp