Extremely bad service

<p>I have been having problems with my Mercedes ML not starting, which has been going on for 4 months now. They picked up a sensor had to be replaced which was done, a week later the exact sam problem persisted. Over the 4 months with the vechile being in and out of the workshop another sensor was replaced. Still the same problem continued. The vechile was in for 3 days recently and the problem was one of the new sensors was faulty. This sensor was then replaced with another new sensor. The vechile was driven outside, I started it and again the same problem persisted. George the manager informed me a few weeks ago that when I bring the vechile in that I must let him know so that he can be involved with the problem. I left a message for him to call me at 11am last week Tuesday by Wednesday afternoon he had still not called me back, so I left another message for him. To date he has still not called me back?????? Now appently the new sensor that was fitted was a pirate part and they suggest to ontain a genuine part to resolve the problem. Now they want me to leave the vechile antoher two days so that they can first get a credit for the pirate part before ordering the new part. I insisted on speaking to George again this afternoon, but he has left and was not able to contact me however my vechile was booked to come in on Tuedsday. I have had to call in almost 30x during last week to get updates and try get someone to call me back. This is SHOCKING!!!!!!!!</p>