Very bad service at OK furniture Jabulani mall

In 2019 i bought a four plate stove at OK furniture in Jabulani mall and they encouraged me to take an extended warranty on it for peace of mind and I did. January 2022 three of the four plates malfunctioned they are slow and no longer as hot as they were the oven also malfunctioned as the top oven bar is no longer turning on. I went to the shop to report this, firstly the manager there was cold and irritated she then told to go make an affidavit so the extended warranty people can come fix it, i refused to go do the affidavit and after fighting with them they eventually sent the people to come fix the stove. When they came to fix the stove they insisted nothing was wrong with the stove and there's nothing to fix when clearly the stove was not functioning like it used to. I am not sure what to do at this point and i am very disappointed with their level of service