Bad service and activated unauthorised overdraft

On October I received a call from two fnb sales representative they both offered me an overdraft I told both of them that I am not interested. I received a call again from fnb the lady was telling me that I'm I aware that I have R2000 overdraft I told her that no that needs to be taken out because I have never agreed to that. Yester day I called call centre and the lady I was talking to did not help me and when I asked to speak to the manager she put me on hold and literary dropped the call. I called back I spoke to stella she transfered me to nkosi nathi and he gave me this email ********** to send an email to complain. I want this to be sorted and I am not going to pay any money they say I'm owing , the money that I was using I assumed it was mine not the banks money . All I want now im going to close this damn account I will rather go to any other bank . Fnb is just ripping me off if it's not unauthorised debit orders everymonth it's their high rates of pricing . And yesterday the was a debit order that bounced simply because of this ****s overdraft they put on my account. And now I have to pay R100.00 for what for the **** stuff you putting on my accounts. I have never had a debit order bounced ever in my life until they put this **** on my account. I have lost trust with fnb I want to close this account finish and klaar.