I think Pandora is a really popular platform for musical artists as well. But I don't know what kind of requirements they put artists through.
one of the companies i pay to upload my music says they send it to pandora. but pandora is not putting it online. you could try to ask them why but i don't think you'll get a response. pandora is a high priority because it is very popular but i don't know how to get my music there. i am paying a company who says they are doing it but pandora does not seem to be accepting it