Nedbank taking money from their clients

Since when is Nedbank allowed to just deduct money off your account as they please? Last month I settled my credit card IN FULL, this month a R2000 DEDUCTION with no permission, no nedbank debicheck, no notification, NOTHING!! In previous months, services I do not belong or subscribe to gets sent to my cellphone number, I decline the debicheck, only to get a notification that NEDBANK has approved the debicheck??? I fail to understand why we pay service fees if nedbank doesnt look after their clients.