unauthorised debit order

Yesterday 14 December I noticed less money in my bank account and checked my statement and saw African Bank debited from my account. I did not authorise it and I did not even get my salary for December yet. I never received sms or email stating that for December they deduct from 14 December. Why? That money not meant for them. How dare they. I get my salary much later and everyone dont get paid by then. I know lots of other people also complaining about African Bank. Wish I never met them. They just take/***** your money. They dont care if you struggling either. Few months back I told them I cant afford to pay my full installment and I need to change amount and term and nothing changed, instead my interest keep rising and I end up owing them more. I am definitely taking things further.