Bad service

I am a small shopper and go to the store everyday to purchase a Chelsea bun or cinema bun and a boiled egg. They seem to have made a shift change and now inform me that I can have the buns for lunch or.buy something more expensive. Then I go to payand the cashier doesn't give my change oh, it's only ten cents! When I try to complain to the guy at the door,I'm told he's busy