How do I download my iTunes music to my phone without a computer?

If it is music you bought from the iTunes Store:

Redownload apps, music, movies, TV shows, and books - Apple Support

If you have an Apple Music subscription:

Turn on Sync Library with Apple Music - Apple Support

If it is music you imported from a CD (for example), you need the computer.

If you purchased music using iTunes on the same Apple ID you use on your phone, go to the Music App, tap Library and either songs, artists, albums, artists and any music in your account which is not on the phone will show a cloud icon to the right. Tap the cloud and it will download to your device.

What do you mean your billing is not accepted? Are you asking about music you have previously purchased or are you trying to purchase music?

You're still not being clear. Music you have already purchased? Or music you want to purchase?