Chances are they're using something like Tunecore where you sign up once, and they redistribute to various music services. You still retain whatever rights you

Chances are they're using something like Tunecore where you sign up once, and they redistribute to various music services. You still retain whatever rights you have, but you collect your income from Tunecore after they aggregate it from Apple, Amazon, Spotify, et al. IIRC, Tunecore does not take a percentage of each sale, but has a yearly fee to keep your music listed using their services.