ALERT READ BEFORE DOWNLIADING!!!

I downloaded this a few days ago it seemed legit and cool not problems at all. I told my friends and they immediately said to remove it cuz it'll mess with my phone I didn't believe them cuz that's what they say about a lot of apps. Couple days later my phone started to lag and glitch out then it froze, I tried to restart my phone it didn't I took out the battery restarted it and the screen went black only saying 'Error Error Data Reset' I didn't know what to do Cuz there weren't any other options so I hit reset. EVERYTHING GOT DELETED, PICS,MUSIC,CONTACTS,MESSAGES,FILES,Etc. It erased everything on my sd and storage. I took it to some dude and what he told me was "have you been downloading live wallpapers apps?" Yea? Why? "An app called walloop recently found in files spread a virus which currupted your data. WTF