How to unsubscribe Smule Magic Piano Apps

Hi there!

I have a situation here. I already uninstalled the Smule Magic Piano app in my ipad, since the subscription cost so expensive for a month. I assume that when I uninstalled this app, it will automatically unsubscribe the app also. But it wasn't. I am trying to unsubscribe now, but I can't find the page in my app store or the ipad.

Can someone help me here?