Welcome to the Community forum, @Tom_R.
Let me direct you to the best possible help handling integration issues with the SportsPlus app so your invoice will show in QuickBooks Online (QBO).
Since you're integrating an app from an external system, I recommend contacting SportPlus support since the integration happens there for them to check if there are internal issues on their system.
Moreover, I also suggest reaching the Intuit Developer team to see the correct application mapping of the integrated app in QBO. Then, guide you to the best course of action to take in attaining your goal.
You can click this link to reach them: Intuit Developer Support.
Also, check out this article to modify your invoices and other sales receipts in QBO: Customise invoices, quotes, and sales receipts in QuickBooks Online.
Feel free to come back here for any QBO integration concerns. We'll be willing to assist you. Thank you, and have a good one.
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