Mtn's poor service delivery

I took 2 phones on contract with mtn 2018 and have been paying on time till December 2019 because I lost my job. On June 2020, I received an email saying I need to pay R1600 and something. Which I paid and even provided mtn with the proof of payment and I was told I need to pay R778 to close the account. When I asked what for and why was I not made aware of it, I got no response. R1600 something still appeared on my clearscore credit score whatever and last month it came back saying I owe mtn R2063, if I am not mistaken. Which I don't know what it's for and how it got to that point. What ****es me off is that, whenever you call those agents, they always say the matter has been forwarded to the legal department, which you can only communicate with via email. There are no contact numbers as even with email, they take forever to reply. Now my life is stuck. I cannot take anything on contract because of this and what frustrates me more is the fact that I cannot get hold of anyone who is able to help. Or are you guys trying to **** me the little money that I have, I don't know. So mtn really sucks and they not professional at all. They treated their customers like dirt.