I received a summons for unpaid hospital bills that the hospital had me send myself. What do I do next?

I paid a visit to the ER some time ago. I did not know that I still had insurance through my fathers work. The insurance would not pay the bills because there was a $3000 deductible that had to be paid first. When the insurance through my father had run out I received my own insurance. The hospital had me send the insurance company the bills myself. Then I received the summons stating that I was being sued by the hospital. I do not see a court date on the summons. I called the insurance company and they said that the hospital should have sent the bills not me. I took the summons to the court house and they told me to write a letter disagreeing with the complaint and send it to the lawyer. Is this the right thing to do. I am 21 and have never had to handle this type of thing before.