Worst client service / *********** technician

Took my car in for service about two weeks ago as VW Mosselbay and was very disappointed when I went to fetch my car. On arrival I start my car to drive home and the idle of the car was below 700rpm and there was a bad rattle noise coming from the engine. One of vw employees was standing outside and told me to take the car back to the service department. When I spoke to one of the technicians at the workshop and asked him on a normal bases what is the rpm that the car idle and he explained to me on cold start the car should idle above 1000rpm and the the revs drop to just above 700rpm. I told him on the cold start the rpm was below 700rpm, then he started the car and said there is no error on the dashboard and that he won't be able to check for me if there is any issues because he don't know where to look for any faults and if the computer box doesn't give him an indication its going to a waste of his time, he refused to assist me on the spot one of the reasons was that he is done working for the day and is on his way home. The manager was standing there didn't say a word and up till today they haven't contact me to makes sure that everything is fine on my side.