Call the hospital and ask for detailed invoice on every bill you have received with a proper breakdown...

The collection agencies are usually a buch of bullys. Don't get intimidated. They threaten with reporting to the credit agencies. But, tell them that you just want to fully understand what the money is owed for and have all the intention to pay. If they continue to bully you, make a counter threat that you will be suing them if you credit rating is ruined because of their careless actions... That worked for me...