Hey there and thanks for coming to support.
We appreciate you posting about this and I've seen a few folks that have had this issue mention this as well. Any provider listed on our Music Freedom page should work just and we do have ways to troubleshoot this and an engineering team that this can be escalated to for a resolution if needed. We don't want folks to feel like there's not light at the end of the tunnel so anyone can Contact Us and get the help they need for this.
Experiencing this with Pyro on iOS. Spotify account won't stream when using tmobile network, but works fine on wifi.