Poor Service

I have a phone contract with MTN, it went into arrears because it was for my son and he was not paying properly and the sim has been deactivated from July 2018. On the 5th September I received an email with an attached letter dated 27 July 2018 saying they are terminating the contract, I should pay R365, 00. Two days after I received another email with an invoice of R1156.73. Then I was confused, I responded to the email requesting clarity but I didn't receive any respond. I called the customer service I was told the account is with the legal department they cant help me. I requested to be put through them they said "they cant" they are not allowed, but they send them an email to call me, until today I haven't received their call. I paid that amount of R1156.73 on the 18th September. I called customer service again to cancel the contract and activate the sim as I have paid the total amount in arrears, I was told same thing again "we cant do any thing the account is with legal and we cant put you through we'll escalate the matter" On the 31st September I called head office because I'm not receiving any services, I was told I should pay R193 they have issued another invoice after paying it the sim will be activated will all the benefits from August, I paid it on the 1st October, the sim is still not active. On the 4th October I called customer service I received same old story and I called head office again, the lady I talked to said she has escalated the matter and I'll received a call latest by Friday. Today its Monday I haven't received any call and the sim is still not active. I'm so disappointed by the overall service from MTN. I don't know when will they activate the sim, the only thing I'm told is to always pay X amount of money. Even now I can't call customer service because there's no service I'm receiving it's just a waist of time and airtime. I don't know now how much now will they say I should pay.