The campaigners founded the Rolling Jubilee project to buy-up distressed loans, where repayments are in arrears, for pennies in the pound and then cancel them free of charge to "liberate debtors at random". That debt will include large amounts of student loans and outstanding medical bills owed by people struggling to meet repayments.
Individuals or companies can buy debt from lenders at knock-down prices if it the borrower is in default or behind with payments and are then free to do with it as they see fit, including cancelling it free of charge.
That's amazing, ingenious, and ****ed up all at the same time. I commend the hell out of those people for their efforts.