Barons makes a mistake and now I'm liable

Booked my car in a month ago for the nationwide handbrake recall, when i was contacted to come and collect my vehicle i was informed that the handbrake check had been done as well as my first service. I then explained that i had not been contacted for approval for the first service to be done to which i was informed that it is fine it's on Barons. A month later after the parts for the handbrake had arrived i was informed that i could not take my car until payment for the service (the one i was informed was free) was settled. I was also told i could not be trusted to make a payment at the end of the month because i could just run away and not pay. I cannot believe i am being held liable for a mistake Barons Bellville has made and then still being made to feel like i am the one at fault. Horrible experience and will never recommend this company to anyone.