Nedbank personal loans division deduct what they want when they want.

I have a Nedbank home loan, personal loan as well as a check account where my salary get paid into. Nedbank personal loans division has this tenancy to just deduct what ever amount they feel like when ever they feel like. They took there payment on the 25th of Sep and on the 8th of Oct went and took an additional R3000 just because they can. I must also stated that I received absolutely no notification or communication of there intention to take money from my account. I feel violated by the fact that Nedbank Banking can just let them take money from my account. If I was at any other bank the personal loan team would not be allowed to just take from my account. Should I change banks to be able to budget???