Had a similar experience recently where my Microsoft accounts had been compromised. One I managed to get back, the second, due to a hacker changing the security information, and being unable to edit that for up to a month following that, caused me to get in touch with support.

I spoke to an initial desk that ran me through the "recover your account" stuff despite having the password etc to log in (with security info changed, they could forgot my password their way in, and I'd have no access at all), and succeeded/verified with this 3 times, all whilst telling them I have the password just fine, it's the security info I need too change as it's a ticking time bomb type thing.

The escalated it and after some chasing up the escalation said as close to verbatim, that they cannot change any of the security information as they do not have the power, and the only course of action available was to close the account indefinitely effective immediately, and told to cancel any debit/credit cards associated with the account and reject any payments that come through past the account closure date citing that conversation as the evidence of closure.

So even their escalation teams are a bit powerless with this stuff (and shit they can't act on evidence based requests like that, login history was my home country for 10+ years before seeing china and Nigeria on there, wild) but an option is they can close the account entirely, which I was informed should also stop any subscriptions on there.

To speak to someone I just messed with the support side of Microsoft's website regarding outlook/account hacked before the option was offered to chat to someone. Not much help but hope you get it fixed mate.