Swopping of parts

I had sent my vehicle in for a service in Dec 2014, the service was excellent. I had recently sent the car in to replace the turbo and check the suspension as the car felt unstable. My fianc? picked up the car for me as I work in Sunninghill and taking time off is difficult. The car felt great and handling much better. I drove the car at night for the first time last week and noticed that when selecting the reverse gear, the light does not work in the taillight. Assuming the bulb was worn, I went in to the Bryanston Vw branch and purchased the replacement bulbs for all the lights. When I removed the rear left taillight this morning, I noticed that it was not the same light that I had before, i.e there are silver shavings on the interior of the lens and the taillight was very loosely attached to the body compared to the right, furthermore, the reverse light bulb was missing!!! I also know that this is not my taillight as I had previously changed the breaklight bulb with an aftermarket variant a year ago and this taillight had no aftermarket bulb in it. No one has touched the car between the last service and the repair. To say I am very disappointed is an understatement.