Can hospitals revoke insurance discounts?

[Kaci1202]

My husband was involved in an auto accident, not his fault, last April 13th. We went to the emergency room that night and told them it was the other drivers' fault and gave them what information we had. On April 27th I called the hospital and gave all the remaining insurance information. We received numerous bills that said we got a $589 no insurance discount, which we assumed was for not having health insurance because we did not, and once we settled with the other drivers' insurance company in June we paid what the bills asked of us. Then in October we started getting calls from the hospital collections asking why we had not paid the remaining $589. I spoke to the hospital and they said it was because there was an auto insurance company involved so we were never supposed to get that discount, but can they do that? They had the insurance company information the whole time, which they acknowledge having, but never used it...so how is that our fault? They have also never even sent us a bill stating we owe the money; so I am just wondering what our options are, legally, seeing that the hospital had the information and chose to not use it. Could someone please help me out? Thank you.