Querry why store close before time advertised

I called the store as it was 16h55 when I was in front of store and doors were closed. The door show 17h00. Lebo gave me Joe number, I called Joe and said he should arrange the doors to be oppened. While I was inside the lady's talked in their language and said I think cause I'm white I can demand the doors to be opened... I mean ...... ****** remarks?????? I need this to be sorted and I need explenation as to why there are such people appointed as managers. I will NOT leave it here.