I can help you refresh the system so it will sync correctly, mervynethelston.
The mobile app might need to be refreshed so it can post transactions such as emailed invoices correctly. Issues in QuickBooks can be fixed by clearing your app's data. This helps eliminate common issues that cause your e-invoices posted twice on the app. If you haven't tried the following steps, I suggest performing them.
Clearing the app's data can be done on the app or on your phone settings. You can follow the detailed steps outlined below:
For QuickBooks Online app:
Android - Select the menu at the top right and choose Settings. Then select Refresh Data and choose Yes.
iOS - Select the menu at the top right and then choose Help & Feedback. Then select RefreshData and Refresh.
In your Phone Settings:
Android - From your phone's settings, select Apps (varies by device). Choose the QuickBooks app from the list and select Storage. Select 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.
After doing these steps and the same happens, you'll want to uninstall and reinstall the app.
Let me also add these articles to learn how the QuickBooks Online app works for you and in managing your invoices: