The service from hell

Took my car into Renault Midrand for service not too long ago and my car came back more problematic that it went in. From after my service found out my battery terminal wasn't correctly tightened leading to my car switching on and off randomly. This got to a point of no return when i got locked out my own car because somehow the loose battery didn't connect at the time and found myself locked out my car. Eventually took it back to Renault and was told all of a sudden other things were broken which is very awkward because they checked the car in the initial service and found nothing wrong and now that their carelessness was fixed all of a sudden things broke. I even told them somehow their mistake lead to the electronics in my car going haywire but was told otherwise. Then to my surprise even after the battery fix these people somehow managed to break the sub woofer in my car. Called them and asked for the manager to personally call me but to this day still waiting. What great service that is !