Yep, i've tryed a lot to send ringtones from phonezoo to my Wildcard. Although, it works for my brothers phone, and he has a super slice.
I contacted phonezoo and told them my problem, and they said that some virginmobile phones work, and some don't.
SO if anyone has a Super Slice, phonezoo.com is the place for you. (There might be other phones, but i know the super slice works, and the Wildcard does not.)