Cell C making customers pay for their mistakes

Over the past few months Cell C has failed to debit my account due to some error with their system. My account has been in good standing, and the amount for the contract has been in my account every month, but the debit order just has not gone off for like 3 months. Anyway, I assume that perhaps we are being given a payment holiday or something, and consequently find other necessities to spend my money on. Today, without any warning my line gets disconnected. When I call to enquire, the very helpful lady says that she’s aware that it’s a mistake on the part of Cell C, however she cannot get my line reconnected. In my opinion, this is absolute BS. It is not my fault that Cell C failed to debit me on time, and are now overcompensating for this mistake, at my expense. I am Willing to continue to make monthly payments, but cannot be expected to pay a huge lump sum now.