When Free Hosting Accounts are deleted from the system, often the domain name is not removed from the x10hosting nameservers. So, being present on the nameserver does not mean that the domain is currently linked to a Free Hosting Account.
Very probably, since you don't know which Forum account the domain was linked to, the Forum account never got logged into. So, the Free Hosting Account linked to it first got suspended for inactivity and then deleted from the system. The nameserver entry was not deleted. If that is the case, there is nothing to recover. No files or databases.
You do not have a Forum account name. You do not have a cPanel name. With the cPanel name, she can search the records. You have a domain name that an Admin has told you she cannot find in the system.