BAD SERVICE FROM INSTALLERS

I have had the most appalling service from one of your installers; on Friday the 18th of September I requested your approved installer (DSTV Installer Boksburg) to assist with signal problems we were experiencing, first we agreed on a time to which they failed to keep only arriving after 5 hours from the agreed time and only after numerous calls inquiring if they were still come, I still gave them benefit of the doubt. When they got here they claimed that the LNB needed to be replaced and that it would cost us R1000 for replacement, I did not believe the LNB was faulty but I let them replace it. 2 days later we were still having connectivity issues and we informed them of this problem; it has however been a mission to get these guys back to our house and try and fix this problem, every single day they claim to be 30 minutes away from my house and they never pitch. At this point, we have access to a few channels not all of the, the catch up (which is what is mostly used in the house) is not working at all nor can we record shows as it comes with a 'recording error', can you please assist us as we have run out of ideas as to how to get these "installer" to fix this issue. I want to come take their faulty LNB, give me my money back and then I will get someone who can actually to the job.