Frozen account by fnb

So my business account was frozen by fnb and they don't seem to give us the actual reason as to why this action was taken. When we contacted fnb, they either make us hold the phone until the call gets dropped or they tell us that the account is still under investigation. The reason for the investigation is because I withdrew money in 3 consecutive days of R5000 each day.

Fnb never gets back to us, they do not tell us the actual person who instructed the account to be frozen the person who laid the complaint. We are frustrated