Hi ,
Thanks for reaching out to Microsoft Q&A.
My subscription has been compromised, and I've received a large invoice. I am also unable to cancel the subscription, even with the admin account
You can reach out Azure billing and subscription management team by creating a billing support request. Billing support request via Azure portal is free for all Azure customers and doesn't require a paid support plan. Please select 'Billing' under 'issue type' while creating the support request.
https://azure.microsoft.com/en-in/support/create-ticket
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