Deduction with no permission

I noticed that an amount of R434.00 was deducted from my cheque account. I chatted to Thokozile via the FNB app and was told that this was deducted to pay my credit card. Firstly I did not grant permission to FNB to deduct money. Secondly FNB has never done this before so why is it suddenly happening now. Lastly my credit card was paid so there should not be any outstanding balance. This is ridiculous that I need to be a premier banker and I cannot get hold of anyone to assist me. I sent an email to *** email address and go this response " Dear Client, Please note that Premier banking mailbox is no longer available for servicing queries.By using the FNB App you can bank safely and securely from the comfort of your home. It’s super easy". I then emailed *** and Jeanette Nteta requested my ID number which I provided then This lady goes and sends me the same response as above. This is so pathetic that a bank this big would mess clients around. I was told on Wednesday that i'd get a call within 24-48 hours well guess what....I am still waiting and its now 120 business hours later and nobody called!!!!