Unfair treatment

I've worked for Klipriver Auto Spares since November 2021. Ever since I've started I've been the best salesperson every week. I've enjoyed working there even though my colleagues was pretending to be happy with me being there. I've experienced no problems until end of April 2022 when I had to leave the company. I left in peace & I didn't take anything from the company. Unfortunately I didn't receive my last salary & when I've approached management about my salary, they mentioned that they took my money for buy outs. Buy outs are motor spares that we order from other businesses to sell to our clients so that we can make a bigger profit. The buy outs that I was charged for is with the company. Which mean I've paid for spares that the company is selling for their own benefit. I have a car at their workshop for repairs since early this year but my car is not fixed yet & they keep on promising me every week that my car will be fixed then I can collect it. I've started paying my car monthly since March 2022 & last month their management have explained me that they took the balance of my salary for the repairs of my car. In total Klipriver Auto Spares charged me over 12k to fix my car which is not fixed yet. They make 100%profit on all motor repairs & spares daily. I would like to receive my latest salary because it's unfair to let me pay for goods that the company is selling for their benefit. I would also like to have my car fixed properly & thereafter have no business ever with Klipriver Auto Spares.