hospital is always greedy

they do not have any rights to charge you the extra +1000 in your case...they knew but they always try their best.

I recently found that my hospital double-charged (for the delivery bill months ago): they billed one of my two insurances, and then they billed me. I did not take note and paid the 10%, and then I found they billed my second insurance and got paid (near $1000) 4 months ago! I found out and called to ask for my refund - they used all excuses for weeks and did not mail me the check until I threatened them with the possibility of using a lawyer and a fraud charge and media coverage (I said that I am sure some TV station will be interested in this double billing strategy). I got the check the next day.