Contract cancellation, easy to get the contract but can't get out.

Im done paying for my phone December 2020 but they continued sending me their data(350mb), sms(50) and minutes(50) that I no longer need. Earlier this year I wanted to cancel my contract. But no luck. Went to mtn store were I got my contract but they said they couldn't help me, all I can do was to call 135. And they don't answer. Went to different stores but same story. Sent an email to them no response. So I ended up stopping the debit, but got grey listed. They stopped my sim that i couldnt make calls. On the 11th October 2021 went to them again and told them they should help with the call then one of their employee called for me and I was able to speak to their consultant, they said I'm owing double what I owed and have to pay before they can cancel. The following 3 days their system was offline so couldn't pay. I just decided to pay that money on the 15th Oct 2021, when I get there the lady said I'm now owing 3 times my debt, she said it's for 3 months I told her I paid, the only month I didn't was September, she said I should call another number but I'm losing my patience here. So I paid the R229 so i can be able to use my phone again. Now I've been trying to call the same number that the guy called but no answer, cause I've paid and now I wanna cancel but still no luck. Mtn is such a shame. It's easy to get a contract with them but can't get out. I'm ****ed don't wanna lie. I dont need that data or sms anymore. Hope you consider getting a contract from them.