Email hacked - I lost total access

Hi community,

I had my email hacked 7 days ago, the hacker changed the password. The problem is that I have microsoft office 365 in that account and I tried every single way to recover my access. Even the ACSR, forms and everything. Nothing works. I got replied back that information provided was insufficient. The problem also is that I created this account in hotmail, maybe 20 year ago. Does anyone know any how to contact Microsoft support? How can I find a channel to support me?

Thanks in advance for any clue you might give me to solve this issue.