Can't change sound settings on my iPhone?

Hello,

I am not sure why this is happening but it's driving me crazy. I like to have my phone on silent (no vibrate, just silent).

I go to Settings > Sounds

Vibrate on Ring is ON

Vibrate on Silent is ON

I change them both to the OFF position. I go back to the Settings menu. I go to Sounds again to make sure they are both still in the OFF position. Nope. They are back to the ON position. I don't know why it's not letting me change them! Please help!

Thanks.