Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
If the subscription is via 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.
If it is via Apple App Store, billing matters need to go through Apple support.