No music and super low fps

So I’ve seen this topic been brought up once before but it doesn’t seem like much has been done to fix it. For a little over half a year I haven’t been able to play the game like I used to-- the music no longer plays (but the sound effects still work) and after my first battle after opening the app, the gameplay fps drastically reduces (I’m talking like 3-5 fps tops). As you can imagine this is a little frustrating and also renders the game practically unplayable. It’s especially frustrating in things such as the dungeon challenges where battles come up every few steps and I only get good fps on the first battle, after which the game lags super slow. I have gotten into the habit of after each battle I restart the app so that I can play the game normally, but this is highly inconvenient. I also miss the music! Please fix this issue!

I’m using iOS 10 on an iPhone 5.

Thank you!