Poor service

I went to chicken locked at park central in Johannesburg (MTN RANK) serial No :10145 to get lunch I order and the lady doesn't ask what flavour cool drink would I like...i let her know I would like a cream soda ....she adds it in as an additional...after noticing her mistake she proceeds to shout at me asking me why I did I add in the cool drink .

I ask how do know what flavour cool drink i would like because she didn't ask She kept on shouting at me