Faulty part and not responding

I ordered an electric power steering pump from Classic Motors North in Durban. They sent the part and it was the wrong part as well as had things missing on it and is faulty. I asked for a refund they said they would first try to find the correct part. It's been two weeks already, I needed my car urgently as it is my only means of transportation and had to make alternative arrangements for it to be fixed as they couldn't deliver the correct part. I want my R3000 refund this is the worst service I've ever experienced -it seems they are just plain *******.