Claiming ownership of domain

Hello,

I recently discovered the amazing activation mechanism of Bentley's product. 
I'm trying to claim ownership of our enterprise Domain but when sending out the request, it shows that it has sent an email to someone, but we don't know who.

Some people that may have created the account have left the company a while ago so I don't know what to do at this point because new users that creates accounts under our domain needs to gain access to their product for an important project.

Thank you