So, now, after two inquiries which were not answered, we learn you have
employer coverage?
With a network.
That is IMPORTANT information.
What you've just posted implies you are retired, enrolled in Medicare Parts A and B, have employer retiree coverage
with a network - which means it is quite likely your retiree plan is an ADVANTAGE plan.
This means that
although you are enrolled in Medicare Parts A and B, Original Medicare is NOT your insurer.
The employer Advantage plan IS your insurer - and this would account for why Medicare denied the claim, saying: "you do not have entitlement for this service"
because
you are no longer insured by Medicare. You are insured entirely (with exception of hospice and ESRD) by the employer plan. Therefore, there is
no coinsurance to be paid by Medicare. Which means, when you are covered under an Advantage plan, YOU pay what the Advantage plan doesn't.
What is puzzling is why Medicare got bills for you at all. All bills should have been sent to your employer Advantage plan. Medicare is out of the picture. Sounds like the out-of-network provider was covering all bases and sent bills to both your employer plan - and Medicare, which should not have happened.
Know that under Advantage plans you are divorced from Medicare.
Instead, CMS pays the Advantage plan insurer a monthly a pre-negotiated capitation rate per enrollee - all bills go to
the Advantage plan, the Advantage plan determines benefits and dispenses payment.
Therefore, if you have an employer Advantage plan, appeals to Medicare are without standing.
If the above is not relevant to your situation, please provide details on your employment status and specific employer coverage - and details on the medical service denied. Saying it is an MD appt. says nothing unless we know the exact purpose of that appointment. No one can help you if critical information is not provided.