Plans and available media disappeared

If you have a Teams/Enterprise account, check if you are not signed in to the private account.

Else, check https://account.adobe.com/plans if the plans are shown. Check also that you are signed in to the correct ID.

If you are signed in to the correct plan and correct level (private/business), and the plan is not present, or the assets are missing, contact Adobe support. For Enterprise/Teams customers, support needs to be contacted by a plan admin via the admin console (https://adminconsole.adobe.com/support).

Private customers can contact support via chat. Adobe customer care can be contacted by beginning a secure chat session at https://helpx.adobe.com/contact.html?rghtup=autoOpen. Pop-up blockers need to be disabled! If the chat window fails to open, or is non-responsive, use a different device to start the interaction.
Support phone numbers may be found here: https://helpx.adobe.com/contact/phone.html. Please note that phone charges may apply.

For support via Twitter:
https://twitter.com/AdobeCare

(see also here: https://community.adobe.com/t5/creative-cloud-services/how-to-contact-adobe-support/td-p/11875703 or here
https://community.adobe.com/t5/account-payment-plan/how-to-contact-adobe-support/td-p/11843852)