*****ulent activity on my account

I’m so disappointed with Nedbank,there is authorised mandate of 3999 from Nedbank personal loan which I didn’t approve .I have lodge a complaint with them and one of their consultants told me not worry cause it won’t deduct.my questions was that why did it lend there in the 1st place I dont have loan .i didn’t get answers because they know is an inside job .I have already cancelled my policy with them because they cannot be trusted.im closing my account