Source code not showing after a hack

Hello

I run the site http://www.catedragavito.com which was attacked and I managed to clean

The problem is when try to access any of the internal page rather than load this page properly, the message from the hacker. If I go to the source code, is correct.

You can see for example this link http://catedragavito.com.ar/?page_id=732 or access the home and try to access any page.

I appreciate any help you can give. Thank you!