My primary insurance was with Aetna and that ended Dec 31, 2016. I have bills from Dec 15,2016 That were not filed...it is too late to file them?
No, it's not too late. The typical window to file a claim is 90 days after the date of service; sometimes shorter or longer. I've received bills as late as over a year after the date of service and had the claims properly adjudicated.
Additionally, it never hurts to try even when it is too late.
I worked in a medical billing office for nearly 10 years. It is not to late to file. You do need to move quickly. Most insurance companies offer a 90 day timely filing period but it varies (some only offer as little as 30 days). Aetna usually offers 180 days. It is ALWAYS based off of the Date of Service UNLESS they have otherwise stated in a contract with the health care provider (that doesn't happen often). Start the process now and even if they reject your claim you'll have the ability dispute it with Aetna and get the claim paid.