Terrible service and theft

In January I called MKT Appliance Services about my dishwasher which was not working. They came to my house to have a look at it, cleaned it and put in a part which they thought was causing the problem. The machine worked for 3 days and after that stopped working again. They invoiced me for R1 350 which I paid. I contacted them again and they came to fetch it. After many follow-up calls and weeks later I was informed that they were not able to get a certain part and that the machine is not repairable. I then asked if they would like to buy the machine for spare parts which Mpilo agreed to and we came to an agreement of R1 000 - seeing that I had paid them R1 350 for a repair which was not successful. After many follow-up calls again, I haven't been paid the money and they are not answering my calls. I have opened a ******** case against them for theft in the meantime.