I have created a Word document which runs to many pages with regard to bugs and failings in the app and the portal. I won't detail them here, but AGL is aware of them and they assure me they are working to correct them. They point out that it will be some months before we can start to see improvements.
I can't give you a specific answer to your problem without seeing some screenshots and having detailed information.
Sorry to hear that your app isn't displaying your billing information. If you have already contacted our app support team, they should get back to you shortly. Otherwise if you would like, you can send myself a private message here on the Community and we can investigate as to what is happening. You just need to provide us with your account details.
As @Richard has pointed out, we are always working to improve our app and have a long list of features that we want to add in the near future!