I'm pretty well stuck on this problem in my iphone 7 (32gb). I've tried every cache cleaning app I could find including Smart Memory Pro for $2 that I saw in the 6s Plus forum but nothing is clearing out the 2+gb of memory locked in this app and the more I stream the more it goes up. The only thing I can do is completely uninstall the app and reinstall weekly to clear out the space. Does anyone know of an app that actually works for them so I stop with this mildly annoying weekly problem?