I called to get an explanation of my bill however ...

I called to get an explanation of my bill however the billing rep said they were not able to speak to the charges because the doctor puts them in. They said I should write in. I then wrote in asking for an explanation of my bill. Rather than writing me back, they sent me to collections. I don't understand why it is so hard to speak to a decision maker. I want to pay what is fair but sending me to collections seems like a drastic approach.