No consistency and lies of operational times

Bad experience on my first time going to your bank, i arrived 15h35 at the door and worse rudely told by the security that the bank closed at 15h30 while time advertised says 16h00, I'm a new client at standard bank but what I encountered to was a real disgrace, we know everyone wanna go home after a long day but you can lie or the company lie saying that the bank closes at 16h00 and the security says 15h30,there's no consistency on this, please sort out this mess and let me know what time is the bank closing.