I have two email addresses, one that the account was created with, as well as the email address you've sent us an email with. I have sent instructions to both those addresses.
To be complete I have pasted the same information below:
To change the payment information on your subscription you would first need to deactivate your subscription via your Settings page at http://twittercounter.com/pages/settings/premium. Once you've deactivated your subscription you need wait for the renewal period to end and sign up for a new subscription, as there currently is no way for us to change payment details upon re-activation. Your subscription is set to renew on the 2nd of July, so if you cancel now, you would need to sign up again on the 3rd of July, when the renewal period has ended. You can sign up for a new subscription via our signup page at http://twittercounter.com/pages/premium.