DSTV Decoders Not Working

I took the special of an additional HD Decoder and free installation. The installers wanted to charge exhorbitant for extra cabling. I got my private DSTV guy to install and the price was much cheaper. My problem is that my decoders (X3) are all not working nor is it working with my fibre. It perpetually comes up with E143 notice of red lines on decoder panels. DSTV is NOT bringing their installers to come and remedy. Shocking,since I had service for 20 years as Premium.