Microsoft has made it impossible to unsubscribe from Office 365

I spoke to my father and he mentioned how he's been trying to unsubscribe from Office 365 for months unsuccessfully. He went so far as to replace his bank card and he's still being billed.

I was of the view that it might be a user issue, so I asked for his password and tried myself.

1. He somehow ended up on the business plan with his regular Outlook email, and you cannot log into the business portal with a non-work or non-school email.

2. No subscriptions show up on his account

3. I looked to find the original subscription emails in case he was using a different account somehow and, no, it's the same email

4. Microsoft has an "advocate" process[0] where you can request someone to help you cancel... but it's broken and raises errors

5. I spoke to Microsoft and they said they're from the consumer side and can't access billing for business subscriptions, and sent me in a direction that gets stuck on the same issue as #1

6. I mentioned this to them and they said they'll have management call back within the hour. That was a week ago.

Through to today, my father is still being billed and caught in this quagmire: it's a business plan but he cannot access the business portal to administer it. I believe he's been paying for about two years now and doesn't use the service.

Does anyone have any avenues to have this resolved?

[0] https://support.microsoft.com/en-us/office/cancel-a-microsoft-365-subscription-46e2634c-c64b-4c65-94b9-2cc9c960e91b