I'm being exploited

In January<br> <br> my family and I were heading to Mpumalanga when I encountered a problem with my vehicle. I received roadside assistance from my insurer (Miway). The vehicle was then taken to the nearest Mercedes-Benz outlet which was in Witbank. It was on a Sunday and we couldn't receive immediate assistance but the vehicle was booked in. The next day we received a call from McCarthy Kunene and they said there were burst pipes that needed replacing for R6000. When I had raised the funds, I called and asked for their account number so that I could pay the money, they restricted me from coming saying they have now replaced the car's petrol pump and they didn't consult with me and then I was expected to pay R14000 for the entire procedure, after raising that amount, I paid it into their account yet I was told I owe an additional R6000 for their labour. These are amounts that were never discussed. I do not know where to turn because this is money I don't have and the store is exploiting me