That’s a rough situation, but you have to understand DH’s position - they are not going to make it easy to obtain credentials in such a situation, as it would be too easy to facilitate a “social engineering” hack if they casually replaced credentials.
Have you availed yourself of the "forgot your password" link on the panel login page?
That should allow you to get login help so you can get to the panel…from there all your other passwords/users are displayable.
edit: I just noticed that you no longer have the email address associated with your account, which leaves you pretty much out of luck on the “easy fix”. There’s a lesson in that: make sure you have an alternative known always good address in the account settings as a back up. ON a weekend, without access to the account password or associated owners’ email box, you are pretty much screwed…which as frustrating as it is, is actually how it should be. I don’t want someone “hacking” my account because they were able to wheedle credentials out of DH in such a situation. I think the “contact form” is your only viable option in this case. .