I am very unhappy

I am very furious and unhappy with the supplier hisence had allocated my repair to, Thula I the service provider came to my house to "check the washing machine" he told my gran he will another the part that burnt and he did, I had to call in and log a complaint at Hisense for him to come and install, Thula I then came back and fitted the part and it got burnt again, he then used my iron to check if it was the plug that had a problem however my iron worked and nothing happened to it he said he will speak to his manager but I never got feedback ... I called them was told a lady was supposed to call me but nothing. I then called spoke to Savanna who promised to call me after speaking to her manager but she didn't call so I called she said her manager said there's something wrong with the plug the same Plug they used to check if maybe it's the plug with the problem, I spoke to the manager who said he will take Thulani's word over mine because he is professional and I'm not and for me that is unacceptable.

I then called Thulani who said that its my Plug that's faulty so I asked him after replacing part with the new one did he check with other appliances and he said he checked with my iron and it worked which means he's contradicting himself and my plug does work perfectly

Is this what you what you do to clients is rip them off so that they can save