Avoid the basic customer service and contact Tmobile through Facebook messanger
to help with this issue.
I see where the confusion is happening - once your account is canceled, online access is canceled as well. You should be able to go the route gramps28 mentioned via Facebook or Twitter to have T-Force get your e-mail address updated for your current account.
I also wonder if you're able to follow these steps to update your T-Mobile ID (email address) or if you'll get an error because it's still associated with the old account.