Contact support

We have an old org set up which is still heavily used, but it is so old nobody knows who the admin is/was? He is probably long gone. But now we need he for some setup. But we cannot open a ticket as only admins are allowed to do that?!? Even if  the admin has left the company we can access his email and will be able to reset his password, we just want to know which mail is associated with admin. Can someone from support contact me so we can clear the this as I am not comfortable to give the org domain in public forum.