Dishonest business that doenst pay seller after successful Auction sales.

I sold my car through Gauteng Auctions in August 2017 and they promised to pay for it in 7 days. They failed to do that until Nov 2017 where they only paid half with other cheques bouncing when they have my car in their possession. Its 9 months later my car is still not settled and I am encurring legal costs trying to get them to pay. The owner Nasir Mahomed always promises to pay the next week and never honours his promises. I have written to them , my lawyer has emailed them and they dont reply to him. This is a dishonest business I wonder how many other people are being treated like this. I will go all out to expose them this is just the beginning.