FNB freezes people's accounts with money inside for no reason

Don't open FNB account if you already have another bank account FNB will call the ***** department of the other bank that you use and inform them to lock your account with money inside so that you continue using FNB only. My African Bank was long since locked and I was told by AFRICAN BANK that FNB locked your account and never give a reason why. This is really terrible what these people do to customers is it a crime to have many accounts same time?