Mecer product purchased at Ellis

Good day

Kindly assist me .

We bought a Mecer invertor from Ellis in Doornfontein .It has been giving us issues from day one .We took it back for repairs at first and because it was taking time ,I had to fight for the product to be fixed quickly .The product was brought back and it was still faulty .We took it back again because it was not responding to the solar panels .Its been a month now and we still have not gotten it .My husband has made numerous visits to Ellis Electrical but they tell us stories either they cant find someone assisting that side or they are still busy with it .We had gone off grid and we haven't had electricity since that time and am wondering if we will ever get the invertor back .The only thing l want for Mecer and Ellis is my refund and nothing else as they have failed us and we are not happy.Please help me as l cant do this anymore .I have failed to get the product back and till now .This is causing too much frustration on me because they seem not be serious .My husband went back again and was told that the parts will arrive Friday but I don't trust it because its been many Fridays .Please help.