As a long-time former resident of Illinois and son of parents who drilled "ignorance of the law is no excuse" into my head from a very young age, I know as a fact that collection of debt is not a criminal matter. Even if it were, it would be local law enforcement, not the ISP knocking at the door.
I've been sued twice. Both times I wasn't served with papers on purpose, because the last thing the plaintiffs wanted was for me to show up in court because they'd lose.
In the first case it was a lawyer who was my landlord. When the apartment went condo, he violated the lease by sending in prospective buyers without prior notice, thus terminating the contract. I didn't know that I had been sued until I found that he had used the secret lawsuit to empty my bank account. Back then I didn't have enough money in the bank to make much of a difference, and he didn't try it again.
The second time it was a cab driver who sued me for personal injuries after he rear-ended me. Because of the ties between certain cab companies in Chicago with organized crime, and because it was cheaper to pay the ransom, I settled out of court for a small fraction of what he was seeking.
Hospitals are another matter. I've seen actual health care workers (not hired 3rd party collectors) threaten patients to pay up or else. I even got a collection notice in the mail from one hospital the day after I visited their ER (an amazing thing in itself, considering I left the ER at 3AM and got the letter at 8AM the same day) even though my insurance covered everything. (I later went to work at the same hospital, and told my story to the manager of the collections department. They feared me from that point on!
If you're uninsured and need urgent medical care, your best bet is to get arrested
. This is what our national health care system has come to.