Hi BarbaraVT,
When switching from the Apple Music subscription to Apple One, you don't need to cancel your Music subscription, it should automatically change on the next billing cycle. You may want to try and reinstate your Apple Music subscription to see if that will help. Take a look at the information found in the link below.
Bundle Apple subscriptions with Apple One - Apple Support
How to get Apple One
1. On your iPhone, iPad, or iPod touch, go to Settings, tap your name, then tap Subscriptions.
2. Tap Apple One.
3. Choose a plan.
4. If you already subscribe to Apple Music, Apple News+, Apple Arcade, or Apple TV+, you don't need to cancel those subscriptions. They will automatically be canceled when you're billed for Apple One.
If you already have an iCloud storage plan or other subscriptions
• Do you already have an iCloud+ plan? Learn what happens to your iCloud+ plan when you join Apple One.
• If Apple One costs less than your current subscriptions, you will not get a free trial so that you can immediately start saving money.
If you are unable to reinstate the subscription, you may want to contact Apple Support by going to Get Support.
Take care!