Hi,
Please check if the mailing account is genuine Microsoft account and not a spam or phishing account? If it is genuine verify your tenant and account/subscription, also check with Microsoft Billing if you find it suspicious over here - https://learn.microsoft.com/en-us/azure/azure-portal/supportability/how-to-create-azure-support-request#go-to-help--support-from-the-global-header
Hope this helps.
JS
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