what am I supposed to do now?

I started off on forums trying to ask for help, they directed me to navigate their contact us area in Microsoft. I then messaged with a virtual agent about my issue and they assured me my problem would be escalated to some team and I would get an email response. couple days go by. Nothing happens so I tried to use the contact us through the phone option I was given. "We’re unable to process your request for a call back. Please try again later." I get this message. I live in New Zealand and am not sure how to proceed.

My specific issue is that my Microsoft account had a suspicious device get a successful login attempt from United Kingdom. I manually logged them out changed my password added 2 factor authentication for both my phone number and email. Despite manually logging this person out through Microsoft I see their device logged in after around what feels like 24Hr (just estimate). But when I check the successful login attempts there was never even an unsuccessful login attempt. somehow the device returns onto the list of devices my account is logged in on and I'm am unsure as to the safety of my Microsoft account. (I am able to see every time I log in and it always shows up)

:)