Please make sure the Sound is set to “ON” on your iOS, not only inside the game (which can be checked by clicking on the Options button, upper right corner) but also in the device itself.

If your game is connected to Facebook, then you can try Uninstalling and re-installing the App as you can recover your account by simply connecting to Facebook again.

However if your account is *not* connected to Facebook, do not attempt this as it will reset your account without any chance to recover it.