Shaming someone isn't something you can do. Shame is something you feel and generate yourself from within. How can you sue someone for something you've generated yourself. Its like suing someone because they made you feel sad.
He probably went off on one because he is desperate to keep whatever customers he has (or had) left. He needs to remember that his customers don't owe him a living, but they will look after him if he looks after them, by doing a good job (in the eyes of the customer) and being prepared to listen to any complaints (whether justified or not) and dealing with them in a calm and professional manner.As for the customer, maybe she didn't want to complain, but bit when he started backing her into a corner. She may have spoken about him to her friends and neighbours, but she has every right to do that. If he does a good job, he will get recommendations. If his work is poor, he'll be out of business. His choice, his problem.John