My battery is bad and it%E2%80%99s run down at 99% I use it when is charging only if not it all run down

Make an appointment at the nearest Apple location to have your iPhone evaluated for free.

Once the diagnostics are complete, the staff will explain your options.

Make a Genius Bar Reservation

Genius Bar Reservation and Apple Support Options - Apple

Or use this link to see if Apple can run remote diagnostics on your iPhone:

Get Support