Ridiculous deductions for a Cellphone Contract

I app**** for a SAMSUNG A55 online and was delivered around July 2024 with nothing else but the phone only in the box. There was no document to explain the terms and conditions for airtime nor data used. It was a contract of 24 months with monthly deductions of R399. Following are monies debited from my account: August 2024: R491,86, September 2024: R453, 99, October 2024: R904.48, November 2024: R5176,07 (this is when I stopped using the MTN sim), December 2024: R8356.42, no deductions for January and February 2025, March 2025: R2311.48, April 2025: R1733.60, May 2025: R3467.21, June 2025: R3467.21, July 2025: R4368.25, August 2025: R3276,19. I would like to understand how much their phone costs because I am no longer using their simcard since December 2024 but the deductions afterwards were too high and ridiculous. I went to an MTN outlet in Nelspruit yesterday and the lady assisting me was just rude and told me that my account has been handed over, I am also struggling to understand that because MTN has been having a way to get money from my account, what am I handed over for because I have already paid R34 006.76 for a cellphone that is worth less than R3000. I want MTN to pay back my money