Money making scam

The owner there rips people off their money especially if he sees that you are a woman and I know nothing about cars he charged me 250 to check what's wrong with my fan ,he then later came back saying he does not know what's wrong he needs to do a diagnostic test on it and I need to pay an extra 350 for my argument is why didn't he charge me for the diagnostic test in the first place .I refused and went home with my car still not knowing what was wrong ...and paid 250 for nothing