In the support article: If you subscribe to Apple One and use a different Apple ID for iCloud - Apple Support Apple alludes to using a different Apple ID for media subscriptions and purchases, and it sounds like you were doing that.
If you don't have access to the account you have two alternatives.
One is to provide a lot more information as to why you do not have access and we try to fix that.
The other is you change the information so you are not using one account for everything.
In iOS/iPadOS: Go to Settings > [your Apple ID] > Media & Purchases. Sign out of your current ID and sign in with a different one.
In Ventura: First, quit Settings. Then, in App Store, choose “Sign Out” in the Store menu, then click on the “sign in” button that appears in the main window. You can then sign into the other account. ( Using different Apple ID for media & … - Apple Community )