The Medicare bad debt requirements state you must bill Medicaid. You should receive a remit showing the denial or sometimes, Medicaid provides a notice for the account. It’s recommended you research why you can’t obtain the RA from Medicaid or find proof to show Medicaid was billed.
For audit purposes, if you’re classifying the account as a Medicare-Medicaid crossover claim, the auditor will expect a Medicaid remit since you must bill Medicaid.