Flawed procedures

How can an established company like FNB close an account without doing their diligence. without contacting their customer without notifying them they just freeze the account and label it as ***** just because of a complaint. When I go to the FNB branch the ***** department can’t even say why the account has been frozen but an investigator will be in touch within seven days how does my business operate within the seven days how is it that you say that you are protecting your customers and you have your best customers interest at heart well we pay exorbitant fees to FNB but we are treated like trash. I would like this account to be open today so my business can operate without anyone contacting me and telling me why a business account was closed off frozen I see no reason this account should frozen. I’ll be happy to leave this bank after this whole ordeal