Connect to Square missed and entire day.

I understand the importance of being able to get your revenue transactions using the Connect to Square app in QuickBooks Online (QBO). Let me help you find a way to import your missing data. 

For you to recover your missing revenue entries within that specific date, I recommend contacting Connect to Square app support since they have the necessary tools to help you recover your data.

You can also request them to get a copy of the missing revenue data as a CSV file so you can upload them by hand to QBO if they're unable to sync those lacking entries using the Connect to Square app. Feel free to see this article for detailed steps: Manually upload transactions into QuickBooks Online. 

You can also utilize this article if you want to learn how to review downloaded bank and credit card transactions: Categorize online bank transactions in QuickBooks Online. 

The community is always around to help you whenever you have questions about importing your data. Have a great day and stay safe.