Trying to make a booking for the Naka Island and there is a package promotion for 4th night free plus breakfast included. However when checking out the rate doesn’t show any discount vs paying for all nights. Fine print says min of 4 to max 31 days and I am trying to do a 5 night stay. What am I missing?

Called to book and was told there is no free night even though the promo title is 4th night free since whatever the total is on the booking screen is what you pay.