a brand new TV malfunction

I bought a SINOTEQ 50" TV at Lewis store orange farm eyethu mall two months ago, according to my knowledge the TV is brand new and it shouldn't be giving me problems however, ever since I got the TV it keeps switching itself off, I had given the TV the benefit of the doubt thinking that it will stop, however the problem is persisting, I have called the store last week and reported the TV, their complaints agent Nzuza said he will revert back to me and will come to check the TV on Saturday however he did not call nor come I am the one who ended up calling him Saturday afternoon to find out where he is and why he did not come, the agent had forgotten about my complaint, I requested him to come and check on the TV on sun day, Sunday he came, checked the TV and even took a video of what the TV is doing he said he will revert back to me on Monday with feedback from their technician however that did not happen I am the one who again took the initiative to call him on Wednesday and demanded for feedback and the technicians number. I am not happy with the product and its state, it cannot be that I buy a brand-new TV and then it has problems that need to be fixed, I want another TV that is brand new and well functioning, I cannot by a brand new TV and in a space of two months it gets fixed, this means from the word go the TV had a problem. as a paying customer I expected a 100% well functioning TV not the second hand they gave me.