Dion Wired (Massmart) not honoring warranty

I bought 2 Xiaomi Mi Boxes in Aug, from the store at MOTS. One now fails to pick up the remote, so it cannot be used. I was informed by the store that they will not help me and I must contact Xiaomi direct. I then mailed their customer service, mail was returned as undeliverable. I then contacted their holding company, Massmart, and they did not even bother to respond. I spent R1500 on a piece of equipment that is now useless, 7 months down the line, and the company that should honour their product warranties refuse to communicate. Unacceptable!!!