Dstv installers want cash ND don't want to take vouchers

Poor service from Dstv. I bought a decoder with installation 3 months ago at Macro Wonderboom and I was told I would be contacted for the installation, later same day I was told they do not cover the area that I stay at ND I was told to contact multichoice to get contacts of nearby installers , well to this day all the installers that I get do not take vouchers they all want cash, they are all saying that it's very difficult for them to claim the voucher , I'm very angry that dstv is selling decoders with installation but at the same time they don't have installers. ND I cannot take my decoder back because I already registered it to my name the very same day I bought it ND I've been paying for it for all these months. No wonder why people are choosing to stream dstv is a waste of money.