Custom-made ringtones stop working after a couple days

I am in desperate need of help.

First off I had been using the app myxer, my friend uses it and has not had any problems. Alas, I have; after making several ringtones and assigning them to individual contacts they working for maybe 2 days. Then when someone would call it would just vibrate. When I checked the ringtones in settings->sound->voice call ringtone only the ones that came with the phone would play.
So I downloaded ring maker, re-made and saved the ringtones and that seemed to solve the problem... until a few days ago when my friends would call all that would hapen is vibration. I'm quite annoyed and don't know what is causing this problem. Someone please help me.
Also, the ringtones I've downloaded from the app Zedge wallpapers and ringtones do not work.

Thank you. It's quite odd, it wasn't working all day till right after I posted this... then I was talkingto my co-worker and was showing them how they didn't work and ta da! they worked ^_^;; If it stops working again I'll try restarting it.

I always feel like all my electronics are on crack... I'm glad to know I'm not the only person experiencing this problem.

Does your screens sometimes go blank (all the apps are hidden) for a few minutes?