If yes - please check both accounts. Is the email address the same or different?
More than likely it will be a different email address. This means that when your client logged in they in fact created a new account.
Disconnect but keep your existing client
With the request in your overview page: Open it and choose to assign to existing client.
Once you've disconnected your client from their original account you will be given the option to select that profile and assign it to your client's newly created account.
Or alternatively, you can delete the new request and your client will simply need to sign out of the new account and sign back in with the email address they originally used to create their client account when they first connected with you (You can check your clients email address in their client profile page).