Line suspended even though account is paid!!!

I don't have a debit order with MTN as they always overbilled me. I pay every month via deposit. I paid my account on 30 May and yesterday received an sms saying my line will be suspended if they do not receive payment??? Today, I receive an sms that my line has been suspended and I must immediately pay the outstanding balance!!!<br> <br> What is going on with MTN???? I demand this matter be sorted ASAP as I need my phone for work purposes and cannot afford a disruption due to pathetic service from MTN. Seems no one is doing their job there, I am highly disappointed. Been a customer for many years and this is getting out of hand now! <br> <br> PLEASE SORT ASAP or I will be contacting my lawyer to cancel my contract with this pathetic \service"provider!"""