Poor service

I am very unhappy customer at this moment and I am being harassed by consultants in the collections department telling me about my overdue account.On the 5th of June bought a Russell Hobbs glass kettle online and collected it on the 10.06.2023 at the Bluff branch,came home with it and it worked that weekend and Monday afternoon to the exact. I returned the item to the store and when I get there the item works. I asked to exchange it for another brand or model but was told with a bad attitude from one lady that I cannot change or return an item if I don’t like it anymore. I explained that it doesn’t work at home I will not buy something and then change my mind. I returned home with the item and till to date my kettle doesn’t work. I have reached out to them via email and on the email again it says I cannot return or exchange my item if I have a change of mind. I have taken videos of this issue and I will not pay for something that doesn’t work in my house but works at the store. I have been getting 3 calls daily to remind me if my overdue account, I was promised a call from a manager by an agent that called me on Monday and I’m still waiting. I even get calls at night to be told about my account. I don’t think I will be able to go back to the Bluff branch as of the bad service or should I say the bad attitude I had received. This is not the first time but I decided to give the store a second chance which I will never refer anyone to use that branch due to the bad service. I am still waiting for a call from higher management, the email I sent still says I must do what I have already done. I need this matter to be attended to urgently and if they want the videos I have to proof this I do have with the date it was recorded.