Have you checked that the information with your registrar is correct? Is it possible for your competitors to hack into your domain name server and change your web server address?
Imagine that you’ve created a great web site which received rave reviews and awards and then suddenly your visitors are directed to your biggest competitor instead seeing your web site.
This could be the scenario if your domain name server is not protected against outside hackers and somebody changed the IP address of your web site or your name servers.
The domain name server is probably the lowest level of technology of your web presence, however many companies forget to secure their DNS.
It’s also important to make sure that nobody can change your domain profile on your registrar’s system.
A registrar is a company which makes sure that your domain is only available once on the global Internet. The largest registrar for .com, .net, .org domains is VeriSign — however they are not the cheapest registrar. They have several systems in place which provide protection against unauthorized changes to your domain setup.