FNB unreasonably and unfairly freezes my account without notice!!

Dear Hellopeter,

Someone deposited money into my account by mistake without my knowledge. They have approached FNB to confess their mistake. I was contacted and made aware. When i wanted to refund the money to them, I realised that FNB froze my account, with the result that i am unable to refund them! Upon investigation i also learn that there is no police case which was opened or any judgemnt against my account. My account was simply frozen because someone went to FNB to tell them that they deposited money into my account by mistake. I fond this extremely prejudicial in that I am a pensioner and with my account frozen without notice I am unable to even buy food. When I approach FNB all they can say is that I must go to the police to open a case. Apparently I must open a case and tell the police that someone deposited money into my account by mistake!!! If anyone must go to the police to maybe do an affidavit shouldn't it be the other person who deposited the money by mistake into my account? I am anyway willing to refund this money if my account is unfrozen. We are talking about an amount of R4800 only!!! Please be reasonable and unfreeze my account.