Hi fi corp has my speaker for more than a month now

I bought a speaker last of last month from HiFi bloemfontein and 2 weeks later in rustenburg at an event the speaker stopped playing. When I returned the speaker they asked me if I tried opening it. I told them I didn't! They booked the speaker in for repairs. Its been more than they're 14 days replacement policy.but they haven't replaced it. I've sent them emails still no response from them. I just want a working speaker or my Money back because the speaker was new and cost me a lot of money