Unable to change debit order date on a personal loan

My salary deposit date changed from the 25th to the 1st and I need to change the date. I contacted the support desk to change the date. After waiting a while I explained what I needed to do and they informed me that I need to talk to a different department (personal loans). The consultant at the Personal Loan department forwarded me back to the previous department. I explained that I need to perform the date change and was forwarded to the previous department. I was then forwarded to the previous department again and then to the other.

They then took my number to call me back and still nothing.

I need to change the date as I cannot afford a bounced payment reflecting on my credit record as well as late payments penalty fees.

This needs to be done before the 25th.

PLEASE HELP!!!