Service failure

I got a call from my mom informing me that there's no water at home. As soon as I was done with my last client I then rushed to pick n pay Greenstone since I work at the mall. Guess what, I got there at 17:56 and the doors were closed already. I even took a pic and video as proof to prove that they closed before time. I then knocked on the door to inform the security that it's not yet 18:00 as their trading hours on the door clearly state that they should close at 18:00. He then came to me at the door and told me that they closed early. I then ask to speak to the manager and he then calls a rendom guy who was passing by to come and speak to me. The gentleman tells me that they closed at 5pm and I asked him why and he says he can't disclosed that to me. I then inform him that I'm going to report pick n pay and he said I can go ahead. I'm so disgusted by how unproffessional pick n pay and their staff are. They didn't even bother to put a note outside to inform customers that they are closing early and no one is even there to explain why.