Highly disappointed at Bosch car service Performer 2000 - Randpark Ridge

I took my car to the Bosch car service (Performer 2000) randpark ridge on the 30th of May 2019 and I only got my car back on the 24th of July 2019 I drove my car for 40kms and on the 25th of July 2019 my car broke down and had to get towed back to their workshop. It's 3 weeks after that now and I still don't have my car back, they assured me on the 24th of July that they fixed everything yet the next day it broke down. They always work on other cars and put you last in line, then when they assure you everything is sorted you find out that they clearly did not go a good job and you have to return it just so it can park there while they work on other cars. You can't even get a hold of the manager (Ashley "apparently") because he is never around and they never want to give you his contact details. If Bosch car services is so highly rated how can they allow this kind of service to happen. What more should I do to get my car back in working order? Can someone please advise.