Block an vaulty account and can pc can acces my vaulty account? Can you block a vaulty account? 
My phone had been stolen and the suspect is one of my friends. They know my lock screen pasword and i was worried if they can acces this vault in the computer and open my private files. So i was wondering to block my account inorder to remove those files.
No, as far as i know, if there are decrypted files on a device that were encrypted by that device, you can't access them from a computer -unless you have some very advanced computer knowledge, which i doubt your "friend" will be that desperate. Here is a link that talks about accessing encrypted data on another device. I know this discussion is about an sd card, but it's still the same idea. You have data in a vault that is encrypted.