I was sent a bill for XXXX with zero explanation. I had not been provided service for a YEAR from this location. When I contacted them, they said it was for a denied service from my secondary insurance. I asked for verification of the service, the denial and all information proving I owed the debt. Instead, they sent me to collections. They did not verify the debt, they continued to attempt to collect on a debt not verified. 
I have made numerous attempts to collect the information to verify the debt, including contacting their XXXX party business management office in California. I have called them repeatedly as well.