Tata incompetence in work

I had my tata bolt in on 4/10/2021 for the engine check light and aircon not working and brakes making a noise, was told the engine check light was on because on no gas in air con and they cleaned my brakes, drove my car to work on 8/1/2021 aircon not working and my brakes still makes the sound but not as much, called tata Oostenberg, the workshop acting manager told me that i have to take the car back so they can find the fault with the aircon and if the gas is leaking i would have to still pay to refill it again this i find unacceptable that i have to pay again for their incompetence in work, and telling me its the system