high interest rate

I created an account with tfg in 2018, bought a few things and started to ppay my account when I got retrenched I notified them and made arrangements to pay. I started to work again and made payments, but the due amount never comes down. there are months when i pay more and months where I pay the required monthly instalment. their interest is way too high and they charge you for stuff that you have never asked for like magazines, sms's, calls etc.

I have sent them an email to ask why the amount never goes down and they couldnt explain that to me I spoke to one of their consultants and she was rude and dropped the phone I spoke to the next consultant who helped me take of all these unnecessary accessories, but the due amount stays the same every month it just doesnt go down. I am 22 years old and this account will keep going until I am 75 years old the way their interest is so high and the account is blocked i am not even buying anything on that account.

How do I go about to resolve this because I've been paying and this just doesn't seem to get any better?