The app on my phone stopped working properly. It is not showing my accounts.

Thank you for sharing your concern with us, @savinggraceholis. I'm here to help you fixed the issue.

The large amount of data in the cache is most likely causing QuickBooks Online app to malfunction unexpectedly and your unable to see your accounts . We can fix the issue in your mobile mobile application for QuickBooks by clearing your app's data.  This helps refresh applications and eliminates common issues and ensure that your mobile app is update to it's latest version.
 

Clearing the app's data can be done on the app or on your phone settings. Here's how to do it in QuickBooks Online app:
 

For IOS version:
 

1. Go to Menu icon and tap Help & Feedback.
2. Select Refresh Data.
3. If you get a prompt message “Caution. If there was a problem getting your latest QuickBooks Online data, you can refresh it now. It may take a few minutes.”
4. Tap Refresh to confirm.
    

For Android:
 

1. Go to Menu icon, then tap More Options ⋮.
2. Tap Settings then Refresh Data.
3. Select YES to confirm.

And here's how to do it in you Phone Settings:
 

• Android -From your phone's settings, select Apps and choose the QuickBooks app from the list and select Storage. Then tap Clear data.
   
• iOS - From your phone's settings, select Settings, then, click on General and choose iPhone Storage. Select an app that's taking up a lot of space. To free up the storage without deleting the documents and data for the app, select Offload App.
   

If issue persist, you can try uninstalling and reinstalling the app, please refer to this article for the steps: How to download the QuickBooks Online mobile app.

For more information about QuickBooks App, you can refer to the following articles:
 

• QuickBooks Online app overview
• Compare mobile app features

If you have any other concerns, let me know in the comment section. I'll be happy to help you. Have a good one!