Hair in food at JOHN DORYS SUMMERSTRAND

I had lunch at JOHN DORYS SUMMER STRAND -the waitress and hostess were lovely ,my son however found a hair in my son's milkshake she called the manager who did not come to my table instead she sent the waitress to make another which I didn't want as we were about to leave ,I asked if they could minus it from the bill which they did , Manager on duty the day disappoints as findings hair in ur food is disgusting,the restaurant was empty she could of made and effort when I went to the bathroom and asked the waiter to watch my son I could see the manager pull a snotty face,I'm very unhappy about the attitude received by "management"