Debit Orders

I am very frustrated with the service i am recently getting at Capitec. we had an agreement that they will debit ( capitec credit card) on the last day of the month( Pay day) which now they debit anytime they feel like. Every month im fighting the same battle with them and its really annoying. I called the call center and was told systems are offline i than requested that they call me back and as always " we can not call you back or send an email we will ask admin to contact you" . All i'm asking is that you debit on the correct date or is that to much to ask for?