The car door won't lock

I bought a car for R65000 the day before yesterday and when i got home i locked the car and went to confirm all doors were locked and the back left door didn't lock on top of that they said they poured R250 patrol on the car and the light was on the light was on and they said the indicator will go up as i drive. I drove home via Elsie's the community with the highest rate of smash and grab with no patrol and and an open door with no clue of both the issues cause i was told patrol was there before i got home i stopped and bought the patrol cause it was clearly empty and i complained to Zahir who changed the story to it was R200 that was poured not mentioning a guy who had patrol was asked what he was doing when he came with patrol and my car was "driven to the garage to get patrol" leaving the one they one they have on their premises with no proof of purchase and the tank on empty. As soon as I saw the door won't lock I got to my phone and told Zahir who gave me long stories with a conclusion that he won't fix the car yesterday i drove the for the door and the disc and registration plate I was on lunch and running late I left the car and he called to say everything was sorted but i wasn't answering the calls he sent a text on whatsapp that the door was fixed and everything fine. I left work to fetch the car a guy came to show that the door does lock but it wouldn't even to him by that time Zahir was not even at work and the guy said that i should speak with him. Cause according to him when i left they closed the door once and it locked and the car was standing there all day to be fetched after the plates were on the car. When i came to fetch it the guy gave me a whole lecture on how that car is locked which later i made out they assumed I was not able to lock it but he had a shock when he also could not lock it and now Zahir says he fixed the door now i must see what to door. These 3 days have been very long listening to one person saying this and another saying that and Zahir on and off work.