Cash crusaders need to refund me some of my money because it was honestly not my fault that Sonboy their sales person gave me the wrong contact

I borrowed money from cash crusaders and I gave them my washing machine to hold they gave me R1200, 4 days later when I went to their store in evaton to collect my washing machine and pay them their money where everything happened they said they thought I was selling my washing machine to them so I should pay the money that they are selling the machine with which was R2000 I paid it because I was desperately wanting the machine. I couldn't not understand why should I pay that amount because it was their sales person's fault that he gave me a wrong contract