Stuck with the vehicle bought from We Buy Cars

I am very much disappointed with We Buy Cars!!! Bought a car (Ford everest) from them relying on Derka report that they publish with the car adverti*****t. When I bought the it was the whole different story, firstly the car came without air conditioning and I had to fix it myself, back seats remail in folded position because electric button is not working, the sunroof is leaking when it's raining and then lastly the Engine is broken. I have discovered that the engine on the vehicle does not match the engine number on the Licence Disc meaning the engine has the different engine number and then again this engine is brocken down, I am not even using the car anymore but I am paying everymonth. All these issues were not mentioned on Derka report which consequently means the report itself is deceiving. South Africa im trying to get these matter sorted but We Buy Cars does not seem to want to meet me half way here. Please help i am stuck with a brocken car and I am paying monthly installments of approximately R6000 every month. Anyone with knowledge on how to deal with such matters please advise. ***.