Take accountability!

Took my car for a routine 15k service check , everything intact and my car is returned with the air con dysfunctional. My air con was perfect when it went it . After I queried this with the head office , I still get the sun around about how this is going to get fixed ??? As if I created this mess ? I need my car back to the condition it was please . Can VW centurion take accountability here and get this right without me following them around !!!!