Mojang migration, lost access

I seem unable to find a way to contact Microsoft customer support, so I am hoping someone can help me here! This is the situation: Many years ago, when my son was too young to have email of his own, I purchased Minecraft (Java) for him from Mojang using my hotmail as the log in. As everyone knows, recently all Mojang accounts were converted to Microsoft accounts. My son who is older now and has his own email thought that he reset the account to his own email; however, it appears that in the migration it may have defaulted to my log in because when he logs on, it says he doesn't own Minecraft. Ironically, I just deleted my hotmail account (a little over 30 days ago, but less than 60 days ago). I am getting an error message trying to log into Minecraft with that account, and of course I can't log into that hotmail account now directly. When I go to the Microsoft account recovery page, it says the email does not exist. However, if I try to create a new hotmail account with the same name as the old one, it says the account already exists. It seems that there's no way to even talk to someone from Microsoft without an account, but I'm in a catch-22 since the account in question seems to be in limbo. I don't necessarily want to reopen the hotmail account, I just want to give my son access to Minecraft. Help?

:)