Do not buy from WeBuyCars - False Dekra Reports and Roadworthy Certificates

I bought a vehicle from Webuycars in Germiston and when purchasing the vehicle they gave me a return guarantee and they also insisted I had to buy the pre-owned extended warranty from Innovation Group as I was buying the car on Finance. 5 days after taking the car home engine warning lights started coming up on the vehicle and I immediately took it back to Webuycars because they assured me that they would either pay for the repairs or allow me to choose a different vehicle. I opted for them to do the repairs. They kept the car for a month then told me to come collect they had done the repairs. I drove the car 5km away from them and the warning lights came on again. I took the car right back to them, they then said they didn't finish doing the repairs they were still waiting for sensors. They then kept the car for another 2 weeks and told me to come collect it again. I did take the car and the lights came on again. On top of that the shock mountings are also not fixed and these were all road worthy relevant issues yet they issued me a roadworthy certificate for the car and a Clean Dekra report. So all this time they have done no repairs to the car and have **** to me. I then decided to take the car to an accredited workshop to get a diagnostic done myself and it turns out that I was right and none of the repairs that WeBuyCars sore they had done has been done. Now when I tried to claim on the Pre-Owned Mechanical warranty which I was forced to purchase up-front, Innovation group has rejected the warranty because the car has been modified. This is a pre-owned car how was I supposed to know what a previous owner has done to the car. So now I cannot claim on my Mechanical warranty because of changes made to the car before I even bought it.

Do not buy from WeBuyCars and do not buy a Pre-Owned Warranty from Innovation group. Both these companies tell lies. They are useless and now I don't know what to do?