24x7 access to Cloud Support Engineers via phone, chat, and web. - HOW?

Hello,

For security purposes, AWS Support doesn’t have a phone number. When you open a support case through the case console, select Phone. You're prompted for a callback number. You'll receive a call from AWS Support as soon as you create the case.

Please see this article for full instructions on opening a support case by phone. Hope this helps. Please select accept answer if it did.

Reference: https://aws.amazon.com/premiumsupport/knowledge-center/aws-phone-support/

so how does one engage support by phone after the case has already been openned?