1
Close any open Office apps.
Use the steps provided on this link to remove the Office licence from your Apple Mac.
https://support.microsoft.com/en-us/microsoft-365-activation-licensing/how-to-remove-office-license-files-on-a-mac
Then log back into one of the Office apps with the Microsoft account you used to purchase the Microsoft 365 subscription.
2
If that does not resolve the problem, log into your Microsoft account on this link, is your Office licence listed correctly there, or if that is a subscription, check the expiry date listed on your subscription, is that listed correctly.
https://account.microsoft.com/services/
If not, go to the Billing section, is it indicated your payment has been processed correctly.