Nothing ever comes from you losing your cool. If you think you're going to get what you need, getting frustrated and insulting isn't going to get you any closer.
Next time ask to speak to a manager. Try to bargain, sweet talk, weasel your way. If not don't give these people the time of day. You're better then that, you're not a child.
Next time ask to speak to a manager. Try to bargain, sweet talk, weasel your way. If not don't give these people the time of day. You're better then that, you're not a child.