WeBuyCars ****med a Pensioner

My mom just recently went on retirement, she used her last retirement money to buy a car from WeBuyCars JHB South, thinking that it's a reliable company to buy a car from. We bought the car from Sfiso (Salesperson), who informed us of the few issues of the car according to Dekra report given to us, which he himself said were minor. A few days later the car stopped working and wouldn't accelerate, the car speed ended at 20KM/H. We took it to car diagnostic and learnt that the car had more problems than what was reported to us in the dekra report. We then went back to WeBuyCars JHB South and informed them of this issue and Mr Chandre from the JHB South asked us to take the car to a RMI approved workshop and send them a quotation. They then declined the quotation and told my mom there is nothing they can do to help her but to buy the car back... we then proceeded with trying to sell the car back to them and they told her that they can't buy the car back in the state that it's in. My mom only got to drive that car for 2 days! And hasn't gotten to reap the fruits of her labour. I'm truly disappointed because WeBuyCars has left my pensioner mother, penniless and car-less. The salesperson (Sfiso) is now avoiding our messages and told us that he has made his sale and won't assist any further.