Then your best bet would be to send them an email to their customer support asking them to fix it or give an explanation as to why. Have you tried testing it with other sites that they host? As in the other users' pages?
Hehe, and make sure you dont have a folder called 'index' with a file called 'php'. 😉
So yeah, send them an email and ask them why, because I doubt that you'd be allowed to change the Apache settings that affect all the users.
~ Paul