Poor Decoder Installation

I wish to raise my extreme displeasure with the lack of quality connectivity with my DSTV Decoder services. Whilst it was installed at the end of 2018,the connections between the three decoders in my residence and TV sets was never 100%. We just left it as it often came up with a red line on the decoders and have to be reset. The TV with the decoder from On Air’s purchase is the worst. I am now told it is out of warranty. This is unacceptable as I expect to have a fully functional set-up with the investment I made into my DSTV set-up.