MY ACCOUNT DEBITED WITH LOAN I KNOW NOTHING ABOUT

I'm so livid... For the past few weeks FNB has been debiting my account with a loan I know nothing about, even handed over my account for reasons I know nothing about. On Friday my account was debited with a loan that isn't mine... I have attempted to call more that 10 times since Monday but the calls aren't going through!!!! **** I'm even considering moving to another bank because FNB Standards are dropping drastically