WaterWorks review: Not honest people

My father hired them to do water cleanup in his basement. The contract says an amount to get started. Two payments and then an amount when done. He paid the three payments and only owed for the last $300. They got an attorney and sued him for the entire amount saying he didn't pay them anything and lied and said they served him with paperwork to go to court. They never did. They served a 40-year-old black male 5'10" with glasses. No one at my father's house fits that description. They are trying to take advantage of an 86-year-old man. Now we have to get an attorney to fight back and show proof that this money was paid because they are trying to garnish his retirement.