The site is lil bit f***ed up but i mentioned the what can be done in a comment below so just take a look at it…
You can download dota 2 from the site given below using IDM or any other down loader.The site is in persian language so make sure u translate it. I downloaded it few days ago and the game is working fine. It just asked for a small update. This is the only site i found which provide genuine backup for steam games.
1.Delete Dota 2 content from your pc if u have put it on download.
2.Now put Dota 2 on downlaod again, download 1 mb and close steam. Make sure there is no running steam process while extracting the game.
3.Down laod all the 8 parts and then extract them to SteamApps folder in the steam library. I’ve put my steam games on E: drive. You can find steam apps folder here :- C:Program Files (x86)Steamsteamapps
4. password:- www.topdownloadha.com
5. Now open steam and validate dota 2.
6.The game will run if there are no updates available.
Other steam games can also be downloaded just search them in the given website.