Abysmal customer care leading to extreme frustration due gatekeeping/stonewalling

My husband received notification on 3 February from MTN that they had not received payment for the account. This is despite payment being made via debit order which was set up by MTN. Phoning the customer careline in an attempt to sort the matter out is an absolute joke. Despite spending 90 minutes on the phone on 3 separate occasions (i.e. 90min x 3 occasions) and specifically requesting a supervisor contact him (as they are never available but suspiciously always in meetings) and specifically requesting on 3 occasions for transcripts of the voice recordings of those calls, NOTHING happens. His original concern for which he received a reference number was closed, yet no-one at MTN can provide a reason for the closure, or in fact, who had closed it. Obtaining the names of the customer care providers , as well as the names of supervisors who were going to call him back has no effect. No-one ever phones him back and every time he phones customer care, he gets a new operator and he wastes another 90 minutes of his life going over exactly what he has told them multiple times before, Additionally, it seems as though the legal department, the billing department and the customer care department are unable or unwilling to speak to each other. Every time your call gets transferred from one department to another he has to go through the rigmarole of a security check even though the call is being transferred internally. Customer care cannot see what legal or billing are doing and each department works independently with absolutely zero cohesion or transfer of information. He waits with bated breath to find out if supervisors even exist at MTN. When he requested that this be elevated to a senior manager he was informed by customer care that they are only allowed to move the complaint up only 1 level, which is an absolute joke. How do you get beyond customer care to speak to someone in a managerial position who can make decisions and see the problem holistically? Whilst all this is going on, he is receiving calls threatening to put him on a credit list.