Desperately trying to keep an ex from accessing my account to stalk me and control other accounts

Someone has been using my Microsoft account for about 15 months to take control of my other accounts. I've been trying for a year to let Microsoft know but can't ever reach anyone I tried again tonight and the message just says for support go to help.microsoft.com there's not even an option to select different topics. It just says that message then hangs up. I checked activity and someone attempted to log into my account starting yesterday. It says I need to use my authenticator app that I don't even have, has a phone number I haven't used since 2014 associated with an account I didn't even create until 2016 and there's another number that I haven't had since 2022 that's linked to an unknown computer. I removed the phone numbers and unknown PC but am worried that whoever has that authentication app will be able to change passwords AGAIN I've been dealing with this over a year. This is a personal account. However I have an ex who's a Cisco certified network engineer architect. I can't escape this. I'm scared bc through their control of my Microsoft account somehow he's able to infiltrate my network, block me being able to use VPN, make me a user instead of having admin access which prevents me from using certain apps, being able to turn off do not disturb, this person also is able to remotely turn on location sharing for any device attached to my networks including my 9 year old I'm terrified and desperately need help. Today's the first day in over 15 months I was able to access this account. Oh and my email is attached to an Xbox live account but I've never owned an Xbox live. However my ex who's the network engineer does. PLEASE provide a phone number where I can talk to a live person about what's happening over and over to me. It's ruining my life. This has been happening for YEARS!! Only just discovered why certain things were happening with my devices ie not receiving 2 step verification codes, codes sent to my email wouldn't work, changing my password but then it immediately won't work, old phone numbers and unknown devices removed from my account but somehow getting added back on giving whoever controls those phone numbers or devices ultimate control over all my accounts and passwords. I could go on but I think you get the point.

PLEASE help before we end up missing by whoever keeps using device location services and somehow turning on location services and blocking my paid VPN subscription from working

I can't say this enough I'm scared for my daughter who's devices are also somehow controlled remotely, sharing pics to a Facebook portal account that she doesn't have and I've never had, filters on YouTube getting turned off so it includes adult content, and her VPN also keeps getting turned off.

My ex had his first IT job with Microsoft many years ago. I deserve to be left alone and safe. So does my daughter who isn't even his kid!!