Replying to Bull shit

So The school I go to gives us free laptops issued by the state for the entire school year for doing work. Me and one of my friends were skiing once in like december and both brought our laptops and chargers and ended up going home with switched chargers. We think nbd and let it stay for the rest of the year. On the last day of school we switch back and pass in everything. Apparently, the charger was 'damaged' and I have to pay a 50$ fee for a new charger. What the worst part is that they won't accept a charger that I buy and send to them. (A Mac charger does NOT cost 50$) Plus, the chargers that they have are like 3 years old and not high quality. I can't bill my friend because they won't pay and I reaaaaaally don't feel like paying. /Rant