we do not do any redirects from our end, and would most certainly not do one to a competitor, the only way it would be redirected is if you added a redirect in your cPanel, or if there's something in your code that does a redirect.
Did you by any chance use them with the same domain previously? It could be DNS isn't fully propagated leaving their IP as a valid IP for your domain on some servers, while your account there is removed and thus they in their turn directs the call to the main site.