[tiwil]

@tiwil

You are right. My phone do need a battery replacement. But this reminds another problem. When your phone model get older it's harder to find original parts to replace. This goes for batteries too. It's easy to find Chinese duplicates but not the original batteries. Another thing is When it gets older phone needs an full OS format. Mine need that. Smart Phone OS's are like Windows. Its not same as those old phones. But my problem is there are couple of apps which I used daily. For some reason these are not available on app store anymore. These are free apps for developer seems to have given up on them.

What's your phone model? For big vendor like Samsung or other android phone, I still found old batteries for my 5 (right now 5) years old phone. Also it's true they sell Chinese model also.

And also, for application, you can do backup on it. You have other phone or not? If you have other phone with Android, you can send it via ShareIt application, that will send an android package extension. Then ask for your friend to send it back. That's pretty easy. That'll only works for Android.
But from your statement, I think you're using Apple phones, right? Because you state "App store" instead of "Play store" or "Google play store".