Waiting 5 weeks for repairs on a vehicle

I purchased two vehicles from McCarthy Nissan in Umhlanga. A 2013 B-class Mercedes and a 2012 VW Scirocco. I took delivery of the vehicles on the 12th August. On delivery the salesmen told me the VW has a bit of a miss on the engine due to the fact that they washed the engine before delivery. The day after delivery the Mercedes warning came on saying the vehicle is 55 days overdue for its service. I immediately booked it for a service with Mercdes. The VW problem persisted and the second time I took it for a drive the catalytic convertor warning light came on. I took to VW for a service as it was also due for its 60000km service. VW contacted me and reported that there was a compression problem on the engine. I contacted Nissan Umhlanga and they collected the vehicle from me to have it repaired. They took the vehicle on the 12th of September and I am still waiting for the repairs to be completed. This is by far the worst service I have ever received from motor vehicle dealer.