I-Cloud payment

Yesterday got an email -

 you are scheduled to be charged $0.99 for your 50 GB iCloud storage plan, but there is a problem with your payment information.Please update your payment information as soon as possible. If we cannot successfully charge your account, it will be downgraded to the free 5 GB plan and your service may be affected.

directions say click on I-Tunes which I can’t find in settings.

my wife got a similar email yet something went wrong and she lost all her precious photos - very upsetting. I don’t want to loose years of my photos - help please.