I have my Family 365 subscription falling due in 9 days time. Back in early December '24, I went into My Account > Manage Subscriptions and selected to Cancel the 365 subscription.
I was immediately redirected to 3 Office 365 Versions Personal 365, Family 365 and Family Classic 365.
I selected Family Classic 365 which cost $139.00 (lot cheaper), but the Family Classic would not take effect until the due subscription date, which I understood.
I received confirmation email regarding the change of versions:
Microsoft 365 Family will convert to Microsoft 365 Family Classic on January 18, 2025. Thank you for switching your Microsoft 365 Family subscription to Microsoft 365 Family Classic. Starting on January 18, 2025, we'll charge the current price of AUD 139.00 including taxes.
The email also confirms what you had said - "The contract says Microsoft will advise of any cost increases."
We'll tell you if this price ever changes.
Since this Copilot/AI issue in Word began in early November, I have not done any further updates to my Office 365, as I did not want it corrupted any more than it already was with Copilot/AI.