Mtn account

I have never complained about any company before, but I don’t know what to do anymore, Mtn cut my phone off 2 months ago, I have been to there shop in Plettenberg Bay 3 times, and all I get is blank stares or pls get hold of legal, I have contacted legal at least five times, they keep telling me a complaint has been lodged and they don’t get back to me, a week ago they came back to me and said I need to pay then approximately R 10 000 to exit my account, I don’t want to exit, I just want to pay my account, a few days later they said I must pay them R 6000 , I asked them to send me a detailed bill, and since then I have heard nothing , when to there store in Knysna to get a bill 2 days ago, and they can’t help me as they say my account is locked, I just want to pay my bill but I want proof of what I am paying for, they keep sending me messages saying be careful of ********. I also want to know why they cut my account off without sending me a message to say what I owe, like they have done for the last 20 years.