bad attitude and rule that doesn't make sense

I just had a bad shopping experience with Pick n Pay Maponya Mall, the ladies working in their kiosk department they are not customer friendly and had a bad attitude. I was with a colleague, and I wanted water, and he wanted cigarettes, so I took the Pick and Pay Sparkling water brand, and we then proceeded to the Kiosk department, when I took out money to pay for my water, I was told that I can't pay for the water at the Kiosk I need to go queue and I refused I told them that I'm buying a Pick n Pay brand and why must I go pay somewhere else. I asked them to show me where it is written that you can't pay any other products except kiosk products, rudely the showed the tills and I still refused to go, and they called a lady who told them to accompany me to the tills. I refused and left the water there. They have lost a sale and a customer. If it was the rule made by management Wow. My question is if a customer wants a cigarette or any Kiosk items are they not selling at the main point of sale?