BANK IS ACTING OUT OF LINE WITH CHEQUE ACCOUNT

A person did an EFT deposit in error into my account during September 2014. The person owed me money for 18 months and I decided not to refund the deposit made. FNB Woodmead authorised a hold on my Platinum cheque account on 3 November 2014 from a person with no authorisation or signing power and without consulting me or any notification whatsoever from FNB. Since when do banks get involved with personal/business challenges and decides who gets paid? A junior person in Woodmead even requested proof of my relationship and money owed to me? I'm totally stunned. I lodes a formal complaint no 622017 with promise to have it sorted in 48 hours. I'm still waiting