Incorrect debit order date

I Have two contracts with Telkom Mobile, one will finish at the beginning of next year and the other had finished in November 2017. For the past 4 years, i have not come across a problem with billing, but this is one month I have. My debit order date in 25th of each month, this past billing went through on 24 November, but because they were insufficient funds in my account, it bounced back. I see the debit order did eventually go off on 30 November. I keep receiving messages that my account is overdue and when I had called the call centre, they advised that it was handed over to collections and that it will only reflect on their side in a couple working days and that I should not worry about it. However I have been charged a fee of R200 for that. For the past four years, the 25th fell on a Saturday a couple of times and would not have the sufficient funds and never experienced this problem before. My debit order is the 25th, you take the money on the 25th and no other day as per agreement. I will not pay the extra R200.