Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hello
I noticed that you put this question in MacOS category. Any chance you might have a separate subscription via Apple account that was signed up through App Store? If so, you want to dispute that one with Apple instead.
However, if it is directly with Microsoft, go to https://support.microsoft.com/contactus, Type "Billing" and press Enter. On the next screen, click "Contact support" at the bottom of the page, then choose "Microsoft 365" > "Manage my subscription". You’ll then see the option to chat with a Microsoft support agent who has access to your account to help review the issue.