Why did the store close early today?

I am really disappointed in Checkers Fairland Walk. I got to the store just before 17:30 and the door was closed. There was a guy standing at the door as there were still customer in the store. I asked him why the door is closed as it is not six yet. His response was that management said he must close the door. When I asked him to call the manager he ignored me. If the stores operating hours have changed then let us know. Put a notice on the door if need be. I really like this store so this was a huge disappointment.