decrease order on overdraft without my consent

I have an overdraft facility that was 46000. I requested for a decrease order of 500 every month. I realised in the 25th of every month the service fees go off and each time they leave me on a negative. I raised this with Standard Bank to say my pay date is the 27 can they please change it to the 27th of each month but they refused. This was last year. Now as of this morning Standard Bank has seen it fit to deduct about 3000 of my money by decreasing the overdraft facility by the 3000. I would like for Standard Bank to rectify this by doing the following: reinstate my overdraft limit as before and change the debit date for fees on my account. If this is not possible, then I have no choice but to report this to the ombudsman and further move my account to another bank. Standard bank will then call me to negotiate the payment arrangements for all the facilities I have with them. I hope it does not come to this. I have sent emails to the complaints department but they were neither acknowledged.