Contact Form Fatal Error
From Joomla! Documentation
The "J2.5" namespace is a namespace scheduled to be archived. This page contains information for a Joomla! version which is no longer supported. It exists only as a historical reference, it will not be improved and its content may be incomplete and/or contain broken links.
There is a fatal error when sending the contact form.
Parse error: syntax error, unexpected 'return' (T_RETURN), expecting function (T_FUNCTION) in /.../components/com_contact/controllers/contact.php on line 172
What is the cause
A bug introduced.
How to fix
Update to the latest maintenance version, which is currently 2.5.28 for the 2.5 series.