Wrong debit order date.

According to my personal Loan contract with capitec, debit order is 25th of every month hence should that date falls on weekends then the money will be deducted on an early date but only from my incoming Salary. This did not happen as at now, rather capitec took the money from my little saved funds that am keeping to use for other means, this affects me because I want to use that money. I went to the branch to reverse that debit till my salary comes inn. They refused giving **** excuses n explanations which does not prior to the loan agreement. I need that money reversed.