Duelbits customer support told me that players should be able to use Duelbits provided that they are not physically located in a banned or restricted region. Banned regions currently include:
Aruba, Austria, Bonaire, Curaçao, France, Netherlands, Australia, Spain, Saba, Statia, St Martin, USA, or any other jurisdiction that the Central Government of Curaçao (formerly the Netherlands Antilles) deems online gambling illegal or are blacklisted.
Always check the Deulbits Terms of Service to confirm exactly what applies to you before trying to access the site.