Ripping clients, *********** Rude.

Evening I would like to lay a complain with. Cash Crusaderss Vosloorus I ask an offer on my HP rp5800 Tower on Whatssup i send one photo i got a respond by Lovely se said she can offer me R500.I asked her where does she get R500 from as she did even check the model. The i was refed to Tebogo. Who he apologise and offered me R1400,wich I was not happy with but as I needed the cash i agreed and send him the clear photos which he didn't ask for, as I'm talking to someone new..i opened the pc to take inside photos. He said I must come to the show. As i was at work i sent my brother, when he arrived they told him the cant take the pc as it was opened and he take the picture. And told him that I threaten Lovely. I ended not even getting that R1400 and wasted my brothers petrol to go there and they don't even look at the pc..i need this to be solved as the taking advantage when you do agree with their offer ,please respond to this as i need the solution in this thank you..