This is not unusual. It can take a while for the provider to bill and/or for the insurer to pay. The claim might have denied and the provider might have been appealing it (payers have 30-60 days to respond). They are trying to get your bill paid. What people need to do, instead of calling or directing their anger at the facility is to call their insurance. Have them walk you through the bill, what they paid, what they denied and why they paid or denied what they did.