The Battle Between Spotify And Apple Heats Up

Even Massachusetts Sen. Elizabeth Warren chimed in about the issue after receiving a copy of the letter, "Apple has long used its control of iOS to squash competition in music."

Related Link: Spotify Hits 100 Million Subscribers, Twice As Many Paid Subscribers As Apple Music

Spotify has used Apple's billing service for several years, which has passed on a 30 percent premium to customers, paying $13 per month vs $10 if charged outside of the Apple store. Apple Music is also $10 per month.

Spotify has been more vocal about having its customers pay outside of the apple store, even offering new subscribers a special $0.99 for three months if they sign up directly on spotify.com. This has upset Apple, which, according to Spotify's lawyer, led to Apple threatening to take Spotify out of the App Store if it didn't stop telling iOS users about the deal.