Unfair phone contract

I went to Edgar's at Gateway Mall in Durban on Friday 13 december 2024 at 10:49, looking for a phone. The people who assisted me were Devashni and Chamaine. As I was still browsing through the phones they offered the deal where i will get the phone and will only pay deposit and rent with airtime for 11 months. I asked for the specific amount to be paid and they told me only the system will tell me, they have to check. They did their process and as soon as they finished they told me that I will be renting the phone with a 100 mb of data that was going to cost me R18 daily for a phone to be active on top of the deposit I already paid .I told them immediately that I'm not happy with the offer they have to cancel it and I will pay for the phone in full and be done with it. They bluntly refused and told they can't cancel, its not possible. I told them I can't buy a phone that only cost R4000 and end up paying more than R7000. They did not bother. I left with the phone after paying R1200 deposit and R540 worth of airtime that was supposed to rent it for 1 month .Now the phone is practically a toy .I cannot do anything with it. I can't even use my email address on this phone now , I have to buy a new phone because this one is useless. The phone I bought was a Samsung A15. I'm not satisfied with the product and I would like a refund.