MUSTARD HAS A FEW SONGS AS CALLER RINGTONES!! HAVE A LOOK AT THIS LINK!! :). http://www.channelx.com.my/mdp/search.jsp?search=mustard.

Celcom Pushes Channel X & Channel C To Mobile Phones | Blogjer ...
Other compatible devices running on Celcom network may have similar shortcuts now. Channel X has been established for quite sometime, with musics, songs, , call me tones and wallpapers as the main contents. ...