Poor service re change of date re Debit order

I have repeatedly called and emailed Sanlam, requesting them to change my date of debit order from 25th to the 1st of the month!!! this has been going on for a year now. Every month I get charged banking fee's for debit orders that run when I don't have funds, because my salary is not in yet!!!! Some months Sanlam actually runs the debit order on the 23rd already! This is unacceptable!!!! Please amend your records accordingly and email me confirmation of this in writing. (Please do not call me, as your agents call at the most inappropriate times)