Hello Giovanni B._377,Good
Good day! Thank you for posting in the Microsoft community.
I understand that you're facing a situation where a customer has switched to a new partner and signed new Microsoft 365 (M365) licenses while old licenses are still active.
Since your concern related to billing and subscription management, it's important to address it through the appropriate channels. Our team primarily focuses on technical support and while we strive to assist our customers to the best of our ability, billing inquiries are handled by a separate department.To ensure that your concern is addressed promptly and accurately, I kindly suggest you submit a support request through the Microsoft Admin Center. This will allow our billing team to investigate the matter thoroughly and provide you with the necessary assistance. You can access the Admin Center Get support - Microsoft 365 admin | Microsoft Learn.
If you do not have access to the Admin Center, kindly reach out to the administrator of the tenant. If you are the administrator and still require assistance, please contact your partner or reseller Find your Microsoft 365 partner or reseller - Microsoft 365 admin | Microsoft Learn.
You can also find the official article containing Global Office 365 Phone Support numbers here: Ways to contact support for business products - Admin Help & Global Customer Service phone numbers - Microsoft SupportYour understanding and cooperation in this matter are greatly appreciated. Should you require further assistance or encounter any difficulties, please don't hesitate to let us know.Thank you for your time and patience.