Provider refusing continuity of care

Has anyone else had this problem? I'm a new enrollee in a dual FIDE SNP as of the beginning of this year in Illinois. I have been getting care from a clinic that doesn't take Aetna Better Health plans for years and was switched to self pay and billed without any warning, and despite a three way call with Aetna and an open grievance they are still refusing to comply with the CMS continuity of care rules (which I confirmed with CMS do apply in this situation) and state protections that basically add up to they're still supposed to bill an out of network provider for 90 days. I received an email from the clinic today threatening to cancel my upcoming appointment if I don't prepay, they just keep repeating that they don't take this plan even though their website says they do. Which whatever, fine but to my understanding they have to bill Aetna anyway for 90 days and pressuring payments or canceling appointments during an open grievance is retaliatory and illegal. Is this correct?