Can't get custom audio files in list

[Pdb]

I have a ZTE Majesty phone with Android 4.1.2 OS. I have created 3 music files with both .mp3 or .m4a extensions (6 files total). After connecting the phone to my computer and using My Computer to look at the storage in the phone, I created a Ringtones folder in the SDcard. I transferred the 6 files to the Ringtones folder. I disconnected from the computer and powered down the phone, then powered the phone back up. The files do NOT show up in the ringtones list.

Can anyone tell where the existing ringtones are stored? I can find no folder in either the SDcard or the Phone which show the existing ringtones.

Is either file extension acceptable to Android?

Is there a new version of Android which may fix this problem, like 4.1.3 or whatever?

Thanks for your help, Paul

 

[Rukbat]

mp3 is acceptable. In my old Gingerbread phone, it required /mp3/ringtones on the SD card. In Jellybean, /ringtones works on the external SD and the ringtones that come with the phones are in Ringtones (the upper case matters) on the internal SD card.

 

[Pdb]

My ZTE phone has only one SDcard (or pluggable module) that I know of. Is this the external or internal SDcard?

When I look at the phone with My Computer, I see SDcard and PHONE. Neither have any of the ringtone titles which came from the factory. Can you tell me how to get to that list from My Computer?

Paul