Cell C does not care, especially at Christmas

On the 20th of December I received an SMS from Cell C informing me that my debit order will run on the 23rd of December, despite my debit date being the last day of the month, I immediately dropped everything I was busy with and phoned Cell C to inform them that the 23rd is not a suitable debit date and that they should please stick to our contractual debit date of the last day of the month. The lady in the contact centre confirmed that the debit order will run as per normal on the last day of the month.

This morning I wake up and guess what, despite having phoned them and requesting them no to run the debit order on the 23rd, and Cell C confirming that they will run as per the normal debit date, they still ran the debit order on the 23rd.

Cell C - HOW DOES THIS HAPPEN?