Re: I can find my ringtone purchase on Itunes app on my iphone but I can't find the ringtone to apply to a contact.
You could try re-staring your iPhone: (Deletes temporary files, re-establishes connections, may update recent changes you have made, often restores order if something is not working.) Restart your iPhone - Apple Support
Else if more help is needed: You can generally REdownload a ringtone:
"Redownload tones purchased with your Apple Account
If you bought tones on another device, you can download them again.
- Go to Settings > Sounds & Haptics (on supported models) or Sounds (on other iPhone models).
- Below Ringtone and Alerts, tap any item.
- Tap Download All Purchased Tones. You might not see this option if you already downloaded all the tones that you purchased or if you haven’t purchased any tones."
Above is from Apple Support's article:
Get ringtones, text tones, and alert tones in the iTunes Store on iPhone - Apple Support
More info. if needed: See: Use tones and ringtones with your iPhone or iPad - Apple Support
More support if needed: There's a "Get Support- start now" link (online chat / phone / email etc.) at the bottom of the iTunes Support webpage (link below):
iTunes - Official Apple Support