Mobile quick books cant see anything any more to do with my account? As in current or old invoices, customers etc. On my PC everything is as normal. But for about month.

Hello there, aholdn.

When you're unable to see any data in QuickBooks mobile app, we can try to clear the app's cache.

For Android: 

1. From More Options ⋮, select Settings.
2. Tap Refresh Data, and then choose Yes.

For iOS:

1. From the Menu ☰, select Help & Feedback.
2. Tap Refresh Data, and then select Refresh.

Once done, restart your phone to refresh the app settings. Then, try to access your account.

If you're getting the same result, you'll want to uninstall and reinstall the app. I've got this article for reference: Troubleshooting Quick-Start Guide for the QuickBooks Online app. 

Please keep me posted on how it goes. I'm here to help you out again. Thanks.