Empty promises and no service delivery

I have ordered a full installation DSTV Explora intallation from Hi-Fi Corp online, the decoder was delivered sameday i paid and when i called them to ask them why there is no installation and Dish together with the decoder and they said i should look for installation voucher which is not there in the box, its been 8 days now and i keep calling their customer care center that keeps on saying they have escalated the matter and they will call within 24 hours which i logged 3 calls in different days , till today i am stuck with a decoder not working.... Ref ***