Are you sure about that 4 year thing? Cause they put it on my credit report and I was told it would be on there for 7 - 10 years!!! They keep calling my work number and hanging up cause they know they aren't legally supposed to harrass you at your place of employment.
Similar situation - this was a bunch of medical bills through Creighton. I applied for financial assistance at the time and was approved, however, these bills had already been sent to collections and they said they could not get them back.
However, at this time time, I also received financial assistance at UNMC and they had also sent bills to collections, but they pulled them back out and applied them to my approval for assistance.