warrantee and service is the worst

good day all . I had my power steering pump replaced by my mechanics shop in Lansdowne Cape town. When I got my car back I noticed after a few day that the new pump was not working correctly. It was whining and going stiff. I contacted my mechanic and told me to bring it back. I only brought it back two weeks later as I was to busy . As the pump was bought at Master Parts , He said he will take it back to them and get a replacement. He phoned me after going to them and told me that they would not replace it and will send it away for checking and that it would take a week. He asked , what is my customer meant to do till then. He was told That i would have to pay for another pump and If they find the pump to be faulty, they would pay the money back for the first pump. I don't have the money to buy another pump. The one they sold my mechanic is faulty. They should have replaced it and now I sit without my car. Master Parts back up service and Guarantee is one of the worst i have seen. They do not care about there customer , only there policy.