Closed before actual closing time and bad attitude

Me and my friends arrived at this branch 15 minutes before closing time to buy a specific item we had seen in store. The staff members had closed the doors and refused to let us in. There weren't many clients in store and letting us in would not have inconvenienced them in any way. Another lady arrived after us and was allowed in. We then went and spoke to the security lady telling her that it's not fair. The staff members were rude and unprofessional. They really disappointed me because this is one of my favourite stores. The service was very bad and the attitudes of the staff was highly embarrassing. I tried calling head office immediately but all the lines were occupied. What bothered me most was that I had asked one of the staff members earlier that day what time the store would be closing. They only let my friends in at 1 minute to 2. With stinking attitudes. This is highly disappointing.