On Sunday's show, Oliver addressed the debt-buying industry and "zombie debt," or "debt that was believed to be settled and buried but comes back to life for collection," according to Time.

The Consumerist reports that debt-collection agencies can buy this debt for pennies on the dollar and make their money by getting just a few debtors to pay. Seventeen states don't even require licenses for debt collection, the website says.

Instead, he had the portfolio sent to a nonprofit that forgives medical debt.

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