There are many registrars who provide customer support from various ways. If you can send email with questions or concerns about their web site, the registrar quickly to respond to support email around the clock.
In case you have some urgency than you have to call to the registrar any time or specific time allocated for customer query. Normally the registrar can provide 24/7 services to their clients to solve the technical or any other problems associated with the domain registration.
