How do I discontinue monthly payment for icloud storage I'm charged.

See these links: Manage your iCloud storage - Apple Support

And particularly: downgrade your storage plan

But better don't post order numbers in this public forum - that is not safe. I'll ask the hosts to remove the number.

OS X:

1. Choose Apple menu > System Preferences, then click iCloud.
2. Click Manage in the lower-right corner.
3. Click Change Storage Plan in the upper-right corner.
4. Click Downgrade Options.
5. Enter your Apple ID password, then click Manage.
6. Choose a different plan to use when your current storage plan expires.
7. Click Done.