Do you believe that the restaurant should have liability? On what basis do you believe that the restaurant should have liability?

Do you believe that the person who complained should be liable to you for your damages? On what basis do you believe that person should have liability? In other words, what did they do wrong that caused you damage? Do you believe that a jury will find that the complainer was acting unreasonably by complaining? Is it possible that a jury might believe that the person was justified in complaining to the restaurant if your grand-daughter was interfering in their ability to enjoy their meal?

What is the nature of what you claim as damages? Is it being "flabbergasted, hurt, embarrassed and angry"? What amount of money do you feel would be sufficient to compensate you for such damage?

Have you been able to determine the identity of the person who complained? Do you know what kind/amount of assets that they have from which you might collect a lawsuit?

How much money are you willing to pay to attorney to investigate and pursue this matter for you? Are you willing to pay an amount that is likely to be far larger (perhaps thousands of dollars more) than any amount that you are likely to recover from the other parties?

What kind of lawyer?? One that will tell you what you want to hear and accept your money to pursue a claim with no merit or chance of success. You have stated no valid legal case. Businesses have the right to refuse service to anyone, plus, they didn't 'throw you out, you walked out. Nobody said you are entitled in life to be free from annoyance, criticism or embarrassment.

The previous answers may have included too much legal jargon for you to understand, so let me put it in simple terms: Get over it and get a life.