Naturals Unisex Salon — Assistant manager behavior to pay a bill

I understand customer dis satisfaction towards d service rendered by d natural staffs. But being a Assistant Manager who s supposed to manage things around, d lady was dying to get d bill amount from d customer before completing d service. I had been to Ananthnagar naturals parlor to accompany my sister who wanted to get a hair cut done and was waiting out with my 1 year old baby. The So called "Assistant Manager" was insisting me to get d card from my sister before completing her hair cut. Don't she have a courtesy to wait until customer comes out!!! Really disgusting. Is this d way the customers r treated???? Is there any rule to pay d bill first and then get d service ???? Such behaviors 'll surely bring d customer counts down :(