My website is redirected to another website.

I have a website named www.XYZ.com. I use worpress as CMS for my website. I was publishing post on my site. And visitors often visited my site. But, my website is being redirected to another website which i don't know. When any person writes www.XYZ.com on his browser and attempt to visit, the site is redirected to www.ABC.com. As a result no one can visit my website now. When they attempt to visit my site they are taken to www.ABC.com. I did not redirected my website. And only i know all passwords regarding my site. I have found no html to redirect in my wordpress's index file. What is the solution?
