Starting from your family to your neighborhood, your workplace and even across the world, you have a lot of people to deal with. But if mistrust and disagreements happen, you have to be sane enough not to use violence to teach them a lesson. Instead, by using candid and carefully phrased strict words, you disarm your opponent and show them what material you are actually made of.
Here are several scenarios: if he doesn’t admit his terrible mistake, be strict with him and tell him his teacher has told you everything and there is nothing to hide. Make him confess and give him the above sound advice. But if he gives it to you in a damaged and unusable condition, rebuke him for being so irresponsible and ask for the price of your toaster.
Be bold and strict in asking for it. He will eventually give in and agree to pay the price. So it’s your win.
Summing up, did you require violence in any of the above scenarios? no, right. That is the right way to handle matters when they go astray. You win while the other party gets disarmed and diminished.