Are you unable to scroll-down the transactions in the Reconcile page, Joyce?
Piled up cache files on your browser can sometimes cause unexpected behaviors or display issues within QuickBooks Online. We can do browser troubleshooting steps to get rid of any cache-related issues.
Log in to your account using a private browser and go to the Reconcile screen again.
If you can access the Reconciliation screen without a problem, you can clear the cache storage of your regular browser.
You can use other supported browsers if necessary.
Let me know if you need more help with this. I'll be around.