Just had a curious idea, can it be paid off with a 0% credit card, then you'd have 12 or 18 months interest free or whatever the promotion is for.
20% seems massive, the interest that a credit card would charge or even a personal loan from a bank would probably be cheaper, by switching the debt from paying the health care provider to a bank the interest would probably be much less, the credit card option could be 0% at the least.
Maybe that's not possible though if an insurance company is involved though, I've no idea on the ins and outs!!