Ok, I managed to dig up the actual e-mail (I only got access to that e-mail account recently).
The swap option does not take an e-mail address, it should only require you to enter the forum name and password, for the account you want to switch to, in other words the one you use now. Since you're doing a swap between active accounts, e-mail should not be a factor at all (unless you try to change that AFTER swapping accounts to the one you have under the other forum account).
I have no control over when the sync between cPanel and server is done (it is supposed to be done rather quick, but various things could cause it to be delayed), however the domain you requested is the one that your site currently operate under. I'll see if I can get a hold of the one in charge of that part of the system, he might be able to force a sync.
This is how the swap screen should look, if you are seeing something about e-mail, you probably is at the wrong screen:
This link takes you to the swap option:
https://x10hosting.com/control/?account&vb&swap (you must be logged in with the forum account linked to the hosting account)