MTN's inability to collect their payments

MTN deducts their payments at the end of the month. In June they did not do so, I enquired, it was a system error. No communication and they affected every customers' credit record as they showed the payments as unpaid. Their error. Now end of January, yet again, they did not collect. I tried to be proactive and get them to investigate. No luck. They refuse to investigate unless I provide my MTN pin and other details. I refuse. They are too lazy to look at the problems and yet again, many customers will be affected.