Account closed with my money inside

FNB and they're investigators stole my money. I've been calling them to no avail no help. They stole my money they closed my account with money inside they didn't even communicate I was the one who kept on calling they busy telling me its under investigation but a month has passed still under investigation. I just want my money back. I really hate this bank I have been banking with them for years but they're service is really bad.