Unhappy customer

On the 27th February 2021 I qualified for R46 000 credit at Lewis Stores in Vryburg and brought the required particulars with me, I then selected the items I wanted which was Sony X10D and Sinotec 50 inch and then the manager took me to Best Home and Electric Express for interview with head office people, the manager now takes me to Best Home Electric so that her staff can sneak in the Sinotec tv that was a display into a Hisense box with no manual not even sealed. They claimed that they did not have brand new Sinotec tv in stock. The manager made sure that I sign before going for an interview with head office lady just to trick me. I expected a brand new Sinotec tv, but instead got a demo and then took it and returned it on Monday 01 March 2021 with the aim of cancelling the contract realising that I was not happy at all with the demo I got, head office then instructed the store manager to give me Hisense of R11 000 instead as a token of asking for forgiveness and the manager said the contract wont change it will stay the same I then took it. The manager then asked the staff at Lewis to come witness when I take the Hisense tv. I then left Lewis store with that Hisense tv after returning that Sinotec 50 inch TV. I then realised that this contract that is not amended will give me problems in future and spoke to the staff at Lewis store but they insisted that I pay the installment before they could amend the contract. I suggested that they amend it before I could pay them. The regional manager was even rude to me, everyone was not even wearing masks, even the regional manager was not wearing a mask either, she then gave me a phone to speak to someone onthe phone claiming that they were from head office to sort out my issue, when she gives me the phone, she does not sanitize it but when I give it back to her thats when she is sanitizing it. She (Regional manager) was even saying that I colluded with the store manager to get that Hisense tv, she said I can even call my lawyers we will meet. She said that I am stubborn and look like some one who is illiterate and not educated. She kept on insisting that I must pay, focussing only on payment not caring about how I feel. She even said that It's better if I cancel the contract, return the items and go somewhere where I will be happy because I give her constant headaches.