OMG I just got the same email to my personal email address as well and had a mild heart attack!!
We have complex registered applications registered that will completely disrupt our organisation if they get deleted. I do remember seeing the phase out notice email a week ago so hopefully that's all this is. Below is the email about this.
Your subscription offer, Access to Azure Active Directory, will be disabled on May 30, 2024
You’re receiving this email because you’re an account administrator of the subscription of offer type, Access to Azure Active Directory.
Access to Azure Active Directory subscriptions were subscriptions that were used to connect to the Azure portal. These subscriptions aren’t required anymore because the new Azure Portal uses your Azure Active Directory access (also known as Microsoft Entra ID), so we’re deprecating these subscriptions. As a part of this deprecation, you can either cancel your subscription now or it will be disabled on May 30, 2024 and will be deleted on July 29, 2024.
If you currently have active resources in your Access to Azure Active Directory subscription, please upgrade to a new pay-as-you-go subscription by submitting a support ticket below.
If you need additional help, please submit a support ticket.