Hello Maria,
Thanks for your email.
It might be the case that Ricardo Teixeira's email address is already in use on wpml.org and this is why you cannot use it in the account.
Can you please let me know the email address you want to use and I will check on this?
In this case, you need to delete the sub-user first and you will then be able to use Ricardo's email address ricardoteixeira@effisus.com to upate the account details.
Let me know how it goes.