itunes ringtones

I purchased song via itunes, I didn't get popup to use it as ringtone.

I downloaded it to XR via itunes, it's in the purchased musis section there and it says DOWNLOADED!!!

it's not displayed in ringtones.

I did let download the ringtones menu in settings with download purchased ringtones button, button disappears.

still not displayed in ringtones.

I did set up itunes on 2 laptops and downloaded that song to the laptops and to the XR.

still not displayed in ringtones.

I tried to edit contact and assign it ringtone, but it's not displayed in ringtones.

would some tell me, before I throw it against wall, how I suppose to use PURCHASED!!!!!!!!! song as a ringtone???