Hi there jwoody,
We understand you're unable to use Apple Music after being refunded for it while subscribing to Apple One, and we'd like to see if we can help.
Get started by reviewing this page: Bundle Apple subscriptions with Apple One
Specifically, the details below may help:
"What's included with Apple One
Apple One includes a free 1-month trial for services that you don’t already have. After your free trial, services that you previously subscribed to are automatically included in Apple One. If you recently canceled a service, you might not be eligible for the free trial. Your plan automatically renews after the trial."
With that in mind, if you're using the one month trial of Apple One, this would not have included your Apple Music subscription, and cancelling that subscription would remove access to that service after being refunded.
Once your plan renews after the free trial, you should then have access to Apple Music through your Apple One subscription.
We hope this helps.