I have purchased arvixe.com hosting a/c coz they give ffmpeg and other advanced functions in shared hosting. But todady when i opened my site it gives me 500 error. and the page was of host1free.com free hosting? how is it possible if i have purchased arvixe and it gives me error from host1free ?? see this screenshot..
Hard to say, you'd have to ask them really... Are you sure your nameservers are pointed towards their servers correctly? Otherwise, I know some providers sell their default pages (404/suspended/other error codes) for advertising reasons, don't know what the case is here though and if you ask me that's quite a conflict of interest!
Do a whois and trace route for your domain name. Check if you have updated the DNS properly and they are resolving to arvixe's server only. As said, they might have sold the 400 page. However, I doubt why would a paid hosting provider would sell the page to a free hosting provider If you could let us know your domain name, may be we have some opinions there!