I just finished my jailbreak, and I've got the same problem with my iToner ringtones. They were initially visible so I tried re-syncing and now they're gone completely...
what you do to get those anoying itoner ringtones away is download ibricker and once you have downloaded it open ibricker and click add ringtones and on the picture of the iphone there should be some random letters just delete them all and they will go away!