Nedbank disgusting service

Nedbank allowed Clientele to make 3 deductions on my account without my consent or authorisation. CLIENTELE debited R415 and R718. 00 on the 19th of December and when I enquired about this they told there was an authorised mandate. I never authorized any payment for the 19th of any month as I don't get paid on this date. Clientele deducted again on the 27th R415 I don't remember authorizing this. I feel that my money is not safe with Nedbank seeing that any company can just go in and take. Will be consulting the NCR and the ombudsman in January