Shocking service

I have taken my Lenovo desktop which I bought on 9 March 2018 from the Tygervalley outlet since it started to "freeze" once it was left on for lengthy periods of time during the day. I took it in beginning of March 2019 (It was before the 9th, since If it was a hardware problem it would still be under guarantee and be fixed under guarantee. I was told by Malcolm, the technical expert at Tygervalley, that it was a software problem and that he would sort it out. I paid something like R450-00 after for this but when I got home it did not want to connect with my wi-fi through the Wi-Fi cable portal to have internet access. I took it back and this is now the best part of 10 weeks that I am without my computer and getting all kinds of excuses why this is happening, one of which was to wait for a Microsoft update during April and which only happened the 1st week in May. I am now really fed up and am considering going to the ombud, if there is one for this industry.