Why do my notification sounds keep changing by themselves?

[AC Question]

I have a Samsung Galaxy Neo and lately the notification sounds keep changing all by themselves. Have I been hacked? Nothing else is going wrong.

 

[B. Diddy]

Welcome to Android Central! Are you trying to set custom sounds of your own, and they keep reverting to one of the preinstalled sounds? If so, are you keeping the custom sounds on the SD card? Make sure your custom sound files are in the main Notifications directory on Internal Storage.