Welcome to iMore! Are you saying the "+" option is unresponsive? Have you tried a hard reset? Which device or phone are you on?
Hold the top or side power/sleep button and the home button at the same time until the Apple logo appears, then release.
7 Reset
Hold the power/wake button and the volume down button at the same time until the Apple logo appears. Then release.
We can better assist you if you register in.