Absolutely Horrified with Mtn

Absolutely appalled by the way Mtn is handling my account. I have been charged a prorata charge of approximately R4000 in January for apparently not upgrading my contract. I did the payment and now they say it's not reflecting on their system. Went instore and did the payment and I dont see the reason why it's not reflecting. Try contacting them on various channels but have been unsuccessful in resolving the issue. Now my cellphone bill is sitting at approximately R6000 and nobody can tell me how/why Mtn has came to that amount. I went to do my monthly payment for my 2 contracts which should amount to R650 but the sales consultant tells me it's more than R6000 owed. He advised me not to do the payment because might end up with the same issue again. Now Mtn has disconnected my lines and I cant use it. The phones are quite important for me as we are working remotely and cant work if we dont have data. This is an absolutely frustrating ordeal for my husband and myself and dont know what else to do.It has come done to me actually logging a complaint with Icasa and awaiting feedback from them. I have been a faithful client to Mtn for the passed 8years and it's a shame the way they treat their existing clients. Any business/company should realise that their clients should always be first and it doesnt seem this way with Mtn. They are going to lose majority of their clientele cos of issues like these.