Unauthorised Random Debits of R2000.00

Nedbank have on 2 different occassions now debited the amounts of R1300 and R1740 from my account, with 5 months apart. No prior call or documents or even sms's have been sent to me informing me of any information on the account. So as it stands they are deducting whatever they want whenever they want, I do not even know the balane, and no attempt to make contact has been made. Email I sent in <br> February was never even answered. Now financially in a problem