Ringtone
Why can’t I change my ringtone when I’ve purchased it in iTunes?
Use tones and ringtones on your iPhone, iPad, or iPod touch - https://support.apple.com/HT207955
Create and manage ringtones. - https://discussions.apple.com/docs/DOC-12051
If you still have questions or problems:
Contact Apple. Click here --> https://support.apple.com/choose-country-region Select your country, then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.
or:
Contact Apple for support and service --> "See a list of Apple phone numbers around the world."
Click here --> https://support.apple.com/HT201232