Poor service

I have called cell c Oct 2019 to change my debit order date to the 1st , I was told that because i have called late the debits has already been run for the month of oct , so my debit order will be starting the following months. I was surprised when they try to debit on the 25th and there was no money in my account, now they busy threatening me that they will cut off my line.Please check your system or listen to your recorded calls as you always says your calls are recorded