I recently made some self-produced ringtones available for iPhone and Android SmartPhones via Tuunes.co/Artists/MaBo
The process was very easy using SnipSell.com as aggregator, and their tech support has been very quick and helpful to answer my questions. I am not advertising SnipSell for any reason other than the comfortable process of submitting my ringtones.
I have been told a few times that people were unable to preview my ringtones;
How To Preview and Download Ringtones from Tuunes.co
First of all, it is important to open the link Tuunes.co/Artists/MaBo on your SmartPhone. At first, you will be guided to the Tuunes website with a list of available ringtones.
Here you can click the links to preview and purchase the ringtones on iTunes and google Play, respectively.
Unfortunately, Apple has exclusive contracts with ringtone providers in Germany and Ireland; and ringtones from independent producers cannot be sold via iTunes in these countries.