Updating of debit date

I am struggling to get my debit date updated. I have been in contact with Cell C support since November 2023 to advise them that I have changed jobs and that my debit needs to go off on the 26th of each month. Every consultant confirms my request is resolved, but every month I am still debited on the incorrect date. My recent engagement was that the system shows that my date is the 26th...but that is not the case. PLEASE fix this...