FNB unfreeze my account

I have been a FNB customer for many years and today I had the worst experience, after writing my exam I received a call from a lady by the name Charity from FNB Forex department, she asked me a couple of questions and I answered her. She said she is blocking my account because of payments I made on my account with money that was sent to me. My biggest issue is that she was not very helpful and she froze my account a day before payday .I will not be able to receive my monthly salary and debit orders will not go through. This will put my credit score in shambles and interest will be added to my accounts,why not find a better way to resolve the issue. How is it their problem what I use my money for?