Bad pathentic customer services

I am from pretoria bought food at nandos florida road in durban yoh what i bad pathetic customer service i received from the waitress and the manager of the food outlet . i went with the glass with a drink inside but the cashier never told me no glasses are allowed and i sat in. The manager told me that i must leave my glass outside unattended. I felt small and i feel that she did not treat me with courtesy (TFC rule)and i had to cancel my whole order. I mean if that is how they treat their customers then they running at business at a loss. The owner will not make profit but will run at a loss. The manager could have just told me that i must put my glass down or finish my glass. I will never refer any family or friends here .