Hello there, @AAA-85.
I understand the importance of having a complete list of transactions in QuickBooks Online. Rest assured, I'm here to guide you to ensure no transactions will be missing.
Banking issues, like maintenance, may cause missing transactions to happen in your QBO account. If maintenance has occurred, ensure to double-check your transactions that it has imported correctly to QuickBooks. You can use your statement as a reference.
If you encounter errors related to your bank, it may also cause the missing transactions. Rest assured, every error you encounter has resolutions.
You can also learn bank reconciling to check for any discrepancies. It can help you identify which transactions went missing.
Rest assured, every transaction will flow smoothly by following the steps above. If you have any additional concerns about missing transactions, feel free to leave a reply. I'm always available to assist you.