Bad service at NMI Durban

I am so put off all Nmi service centers ,especially the Ols Fort Road branch.their service is pathetic.You take your car there expecting it to come out good after a service but this is not the case.on the 12th of August 2019 my son took his Merc for service and since there was a whole list of things that needed to be checked out so he told them that the car can be kept at NMI for a few days.The next day around 3pm they called him to say car was ready for collection and all work was done on the car. I collected the car and drove it home ,north beach which is 15 minutes away.On driving the car the next day the battery light was coming on.Mercedes on call had to be called to tow the car away back to Nmi as the technicion said it was safer not to drive the car back to NMI.note this car was just serviced??????