Worst service

I don't know where to start,I bought a car at Nissan Nigel,they promised a free cash back of R10 000 and later changed it then added it on my account,I questioned it then they came back to offer me R5000.00,I accepted it since I wanted a deal to just conclude even though it was not as promised initially, Am still waiting for my trade in balance and the cash back balance that they already added on my account and the one promised,Absa settled them but they are unable to give me my money back.There is no accountability and integrity from this business and how must I refer my friends to such business?

They keep on saying Karel is busy with customer and he is forever not available, I feel alone and regret ever buying a car there.