Mall closing before before stipulated closing time

We went to Cradlestone mall on a sunday afternoon. We entered the mall at about 16:53pm, but almost all the stores in the mall was already closed and locked up with their lights switched off, the staff clearly long gone. Some stores had security guards refusing entry to customers who wanted to enter the store. The trading hours of the mall is clearly stipulated on their website as being open until 5pm on a sunday. Luckily Game was still open and we could make our purchase, but I am just surprised that all stores do not adhere to the same trading hours. Surely this should be standardised throughout the mall?