I'm an apprentice electrician. My employer insisted I work 10 days straight without a break. On the 10th day I told my employer I was really fatigued but he said I had to work. When installing a solar system to an unfamiliar roof, I broke some tiles. I used the customer's spare tiles to replace the broken tiles but now my employer wants me to pay $400 to have the roof repaired because the customer complained about the broken tiles. Is this fair?