Former insurance carrier recouped payment for claims from former healthcare provider. Am I going to be responsible for re-payment of the provider?

Before I turned 26, I was insured under my father’s health insurance plan until 09/30/2021, and because we live on opposite ends of New York State, I was enrolled individually as a guest member under their Away From Home Care plan with a host insurance policy to be seen by providers local to me so they would be considered in-network. I thought this coverage with the host plan must remain active as long as my home plan was active, until my 26th birthday in September 2021, as I never received documentation from either the home plan or host plan stating otherwise.

However, prior to my birthday in September 2021, the host plan began to deny claims with my provider, and I was informed that my host plan coverage had retroactively been terminated 02/27/21 by my home plan. The home plan says that while I was still covered by their policy until 09/30/2021, I lost coverage with the host plan because their Away From Home Care membership had an expiration date of one year from enrollment. Neither I (the insured) nor my father (the subscriber) and not even the host plan have any record before September 2021 of 02/27/2021 being the scheduled/anticipated date of termination or that I agreed to a membership term of only one year. In fact, I only have dates after the fact where my coverage was confirmed by the host plan. The most recent insurance card mailed to me by the host plan is dated 06/09/2021, and I also have records of phone calls I made verifying active coverage with the host plan with the latest occurring on 08/06/2021.

Now, two months ago, I was contacted by the same former provider above because the host plan recouped payment for additional past dates of service, between 03/05/2021 and 06/01/2021. I am unemployed and currently covered by Medicaid due to lack of income. Paying out-of-pocket for the payments rescinded will be an enormous financial burden for me. I would never have made any of the recouped appointments with this provider if I knew my coverage was no longer active after 02/27/2021, just as I stopped seeing the provider in September 2021 when claims started to be denied. I’ve made dozens of calls to both the former home plan and host plan throughout the last few months to ask to speak to the right representatives, requested documentation (though none has been sent), and wait for their calls as they looked into the case. I am not well-versed in health insurance, is this a situation where I could appeal the claims, even though they recouped payment 16-19 months after service? I was relying on the information the host plan gave me, which I could only assume to be accurate and trustworthy. Do I have any leverage because the host plan continued to send me new (and unsolicited) insurance cards until 06/09/2021 and confirmed active coverage on all instances looking me up in their system during phone calls through 08/06/2021, but retroactively says I was inactive as of 02/27/2021? Or am I truly responsible for paying this amount back to the provider?

TLDR: I received inaccurate information about the status of my coverage with a health insurance carrier who previously hosted me as a guest member to access local healthcare providers. Over a year later, they recouped payment from a former provider who is asking me to pay for the amount the health insurance carrier rescinded. Throughout and after the dates of service in question, the host plan continued to confirm that I was a member with active coverage. Do I have any recourse, or am I responsible for the payment?