dissapointed in service

I recently bought two vga monitor cables worth R250 each. My computer broke so I had no use for it. I never opened it and used it, it is still sealed in the boxes. The guy working at cash crusaders ddnt want to buy it at first. Than later offered me R40 for both. Im not upset abt that but what im upset abt is that he gave the guy before me R400 for his cables. It was my first time wanting to sell something at their shop and truely the last.