First, confirm that php mail is working by using the most basic test script possible and nothing else on the page.
PHP Mail
If that goes through then we know it is your coding or a conflict somewhere within.
If it doesn't then you need to do a ticket so the admins can go through mail logs to see what is going on, if it is leaving the server, or if php needs a recompile(99% of the time it isn't the case.
Just be sure you give them all the info like the URL to duplicate the problem, email you are sending to, etc.