I can't cancel the auto-subscription for my premium account

[A Former User]

I recently noticed that my premium account auto-renewed, but I didn't want that, so I tried to turn off auto-renewal on my account, but the original email address for this account is no longer available, and I can't receive emails when I try to manage subscriptions using onfastspring. And when I change the email address tied to my account to another one, I still can't receive emails from onfastspring, so how do I cancel my auto-renewal in this case?