Closing the doors before the time indicated

I went to buy oil from Hinterland Amersfoort this afternoon at 16:50 the door was closed but I thought it was due to the coldish weather. As I approached the door the door was shut close and locked right in front of me. When I got into my car, the workers came out and went home. This is unacceptable, if they indicate that they close at 17:00 they should only close their doors at that time but even the staff all left before the indicated time.