Hisense tv breaks twice in a space of 3 months

I purchased a Hisense 40\ LED TV on 09/08/2015 for my dad. The tv started giving us problems in November so I took it in and they repaired it in December. In March again the tv has no picture and only sound, so I took it to Makro and they said there is nothing that they can do except log a report with Hisense. I don't want the same tv as it is clearly a defected tv and I requested a replacement of a new tv and I am willing to pay more for a bigger one but Makro refuses. The want me to run around instead of assisting us with this matter. Their lines are continuously busy and this is so frustrating as Makro said they logged the call twice but I haven't received any call from Hisense. Makro staff don't take any iniative to follow up. I am so upset and I want a brand new tv as this is ridiculous and I am paying for it, not as if they giving me anything for free."