IPHONE SETTINGS WON't CHANGE FROM DEFAULT?

So my sounds/ringtones are all in default and when I try to change them they won't change, it's not frozen just when I click on a non default sound it changes back. My reminders all got deleted along with my calandars. Also the battery percentage display in the top corner will not show up when I try to change it. This has been very annoying and I need to know how to fix it.

Try a hard reset. Hold down your power button and home button until the phone turns off then turn your phone back on.