Hello 40constance,
Thank you for reaching out in Apple Support Communities. If we're understanding correctly, you're unable to create a backup of your data to iCloud and you're concerned that the iCloud storage plan did not transfer to your new iPhone. We'll be happy to help.
We recommend to verify that you're signed in with the same Apple ID account from the previously used iPhone. To verify that please follow these steps: Sign in with your Apple ID
Then, let's review the available storage space that's available in iCloud. To do that, please follow the section that says, "Get help backing up your device with iCloud Backup" in this article: If you can't back up to iCloud or restore from iCloud backup failed
We look forward to hearing back from you with an update.
Kind regards.