Poor parts service

I went to Tommy Martin with sample parts and requested for RFQ. after supplying the vin number and the sample a quote was given. I then handed the quote to my client and he bought the parts from barloworld city deep branch. When we received the part we had a look and the parts were not the same as the sample. i went to tomy martin roodepoort and told them they gave me the wrong part number and i was told by parts division it is the correct part number. The client took the sample to the city deep branch and a other part number was given to my client. now city deep branch refuse to exchange the parts cos we supp**** the part number that was given to us by roodepoort branch. Now i have to pay for the mistake roodepoort branch have made due to wrong part number supp**** to me and a possible standing time penalties that might occur as the car is been use for business.