To top-up a Nauta account through Ding you must have an active permanent access account, set up with the domain @nauta.com.cu or @nauta.co.cu and add the account your contacts list to have the Nauta option available.
@nauta.cu only relates to an email address and is not an access account.
When sending a top-up to a Nauta account, please make sure to enter your information correctly as account details are case sensitive.
The owner of a Nauta account can check their details with ETECSA Business Information Service by dialing 118 (from within Cuba).
For information and service rates, please visit http://www.etecsa.cu/?page=internet_conectividad&sub=internet