Worst Service - Not helpfull at all

The company bought a TV at N1 City- HI-FI Corp - Capetown , the first tv we bought only worked for 3 weeks , we took it back at hi-fi corp , and they gave us replacement when i installed it and switched it on , the screen was damaged I took it back , the store manager by the name of Danie, he argued that the tv was checked and it was fine, I asked to see footage ,he refused to show me the footage , he said the slip serial number doesn't match the serial number on the tv , I asked him to show me the serial .we than found out that tv didn’t have the serial number , the one on the slip was for the first tv we bought, he made accusation that we swapped that tv, I questioned how did they issue us with a tv that didn’t have serial number he didn’t answer , he said he was going to investigate on how it happened ,I left the tv with them later on they called to say all the batch they had that time didn’t have serial number , we recently fetched the tv from them as we are not winning with them . the worst people to deal with .