Billed but no service

I recently complaint that I didn't receive my pricelock deal and I was billed for it. Then some greedy sales agent activated my normal decoder on price lock without my consent. I am billed R225 for this mistake and no one seems to bother. Today I once more queried why my installation have not taken place I was told that DS Smart Technologies have never received the decoder and can not install it. Now I would like to know where to do I send my next complaint as dstv billed me and doesn't care to provide the services they promised on our agreement.