You had an account ? Bought credits ? Then........downloaded and installed ?
When installing again, you must have created a new account. Instead of registering with the existing one.
You should be able to sign in to the original account, as long as you have the username and password. Once you've done that on site, the GUI should pick up on that. If it doesn't immediately, try quitting and restarting or logging out and back in again.
You can then ignore the empty second account.