credit checks done without consent

I went to FNB to open an account that will be linked to my paypal and one of the consultants advised me to open an easy account of which I did. days after I received a notification that a credit check has been done on my name from FNB. I went back to the branch to ask why an enquiry was done and I was told that it is part of the process and how the system is designed. Why do you guys perform credit checks without my knowledge let alone my consent? I am very angry as I was avoiding to do credit checks at all costs and now this inconvenience! I am so disappointed with FNB as well as the consultant who assisted.