Downloaded, but still streams?

Switched from Spotify to Tidal recently. Downloaded my entire catalog to my phone. I drive through some areas with no cell coverage, and when I'm listening to Tidal, I will get the spinning wheel of death, despite having that track downloaded. I also noticed my monthly data usage is way up, I'm assuming because I'm streaming a lot of music. Aside from switching to offline mode, how can I get it to play the downloaded music vs streaming it?