Took my money and takes too long to refund

I have a homeloan with standard Bank since October 2016. I have had my premium paid from my salary for most of the term so far. Since then standard bank has debited my account 3 times, as they say by mistake, even though it comes off my salary. On Friday 27th July the same thing happened again. I called in and they logged my complaint and I was told that it would be resolved by Monday which was yesterday. Yesterday I called and I was told that the matter has been escalated and it will be resolved by 12h00 the next day which is today. I called standard bank today and explained the urgency of the matter as I have insufficient funds to make my payments. I was actually asked for a letter to cancel the debit order. Firstly why would I need to do that when standard bank took my money without my permission and for the third time now? Why is it so quick to take my money but such a tedious process to return it? This is theft and an extremely inconvenient time, as it is month end and the last day of the month, to have to deal with a matter like this. A company like standard bank, which has been my bank for as far back as I can remember, should have measures in place to make sure they are the ones that pick up on their own mistakes and not expect their customers to have to take time to sort this out. As I said, by tomorrow I need to make payments and I have wasted so much time since Saturday trying to sort this out, when it should have been standard Bank noticing and fixing this! Two installments for 1 bond and they cannot notice this?! Such a long process to get back what is mine? Absolutely unacceptable!