How to get my app to open again?

So only this one app doesn't open well it does then closes fast and don't say delete it and download again because the app is a music app that Apple has taken down from the App Store because of free music, also my sister has the same app and it works perfectly fine on her iPhone so don't say it's because Apple took it down please help I have all my good music in that app

There's a way to use your sister's version on your iPhone/iPod/whatever you have. However, it does require a jailbreak which is against Apple's terms of service and will void your warranty (if you have one). I'll tell you how past that once you figure the first part out.

There's no other way because Apple locks down their Operating Systems. That's one reason why I will never purchase an Apple product again (There's thousands of other reasons too).