Debit order

I have debit orders with the bank that is suppose to go off on the first of the month and dont normally have problems other than that they sometimes go of later than the first of the month, but I always make sure the funds are available. This month Standard Bank took it upon themselves to make a deduction on the beginning of the month as normal, and then again on the 18th of the month just because there were funds available to deduct one of the orders, leaving me R 3500 short. As I plan when I will spend my money, I left the funds to use this week. To my surprise there was a substantial amount missing, leaving me high and dry until I get paid on the 27th!! When I went to go and complain this morning at Strand branch, tke clerk just laughed and said the same happened to them and Standard bank decided to deduct the money earlier because everybody got bonus this month!! I did not get bonus and have to manage my money. It is therefore not safe for me to leave my money in my account, as they do no stick to the contract we have to deduct my debit orders at the beginning of the month. This is unacceptable service and I wonder to how many clients did thin happen to??