MTN payments issue resolved last month but amount still shows in 30 DAYS OVERDUE

This is now disgusting of MTN. I had an issue last month with MTN which I made the required payments ect.. and even a person from the complaints department contacted me and sorted this out so I assumed everything was fixed HOWEVER now get my new statement and the last amount I paid to settle the account issue is now showing as 30 DAYS OVERDUE. Is their accounts department *********** in allocating the funds or what as this is unacceptable and this they have to sort out asap, I want a reason as to why it has not been allocated as yet as this should have been and I want an apology. Sending to MTN's email is useless as no one bothers to contact me back. This will be resolved and sorted out today. I am sick of dealing with this issues from MTN and I know of people also having problems about MTN's accounts. I am giving MTN a warning now on this if they take off more than what they should be taking off when my account gets debited I will be doing a reversal asap and will be changing my plan from debit order to manual payments

Sent an email to their complaints email but yet to even get a reference number

Kind regards Mr Klopper