Hello @Tallhog,
Good morning, thank you for posting in our Community Forums! I can definitely relate to wanting to know how much data you have and for how long. I will be happy to share another option on how to check this and will send your request up the appropriate channels.
We are constantly improving and making changes to our app and website, and we appreciate all the customer feedback we can get on how to continue to improve. Hopefully, you will see the graph reappear in the near future.
You can check your data usage for the billing cycle when you log in your MyATT account in a browser on the home page. You can also check it by dialing *DATA# or *3282#.
I hope this helps have a great day!
Daniel, AT&T Community Specialist