I lost my R18 950 to a car dealership company We Buy Cars

On the 16th of December 2019 I bought a car make Mitsubishi Pajero from this company "WEBUYCARS.co.za The Car Supermarket" South Gate brunch in Johannesburg. I was attracted by the condition of the car and the service history, I spent R68000 pluse R950 for licensing.I left the dealership before 3PM but after a few kilometers I round out the car had a problem of struggling to move . I called the salesman telling him about the problem and they had already closed I can come back the following day. The next day I went there at about 9am the salesman Benny Mhlongo logged in my complaint and the sales manager would help me. The sales manager said that if I bring the car now I trading it in with the vale of R50 000 to take another car or I am selling it back to them for R50 000 which was not an easy thing for me to accept. He told me that if I'm not happy I can go and complain to their complain department which I did,later on the day they came with a better option that they are going to take R5000 and they gave me 1 day to look for a car that's R63 000 from their other branches and that suited my affordability I ended up being forced to take their R50 000 offer.They payed me back the R50 000. I lost R18 950 , I have tried to ask their complain department to review my complaint beginning of this year and I failed to get my complaint through.

Can Hellopeter please help me