Notification tone problem

[CrvyloOo]

I have an LG Optimus Elite running what I believe to be Gingerbread (2.3 something). I used one of the many "Mp3 to ringtone/notification tone/alarm tone" apps in the app store to convert some of my mp3's to what have you. It was working just fine until today, after unplugging my phone from USB from my computer. The notification tone reverted back to the default one. Now the tone stays as the default one, no matter which tone I set it to use, whether it be one I made from the app, or one of the ones that were preset in the phone. I've tried uninstalling the app and installing one of the other apps that do the same thing and creating a new notification tone to use for the default, but to no avail. The tone still plays the built-in default tone whenever I receive a text. Does anyone know how I can fix this? Thanks in advance.