I'm tired

Tired of mtn really ,I got a month to month home internet wifi on December 2024 it wasn't working apparently one lady on mtn said there were not suppose to sell me 5G in my area it's not working..so on 16 of January 2025 I returned it to century city mtn store I filled out their form and game Irms number and said I must do a follow which I did.but no one was able to assist me.even on their cancellation department.and they debited my account end of January and February..but they stopped from March till now..but you know what I'm owing them R6600 ,they handed over my account to legal team asking money for something that is no longer with me and didn't use it..this company is acting like as ****a shop while it's a big company..they ruining my credit score very badly..I'm so depressed because of them.