Let's get this issue sorted out, @ka1959.

QuickBooks Online (QBO) displays the entries at the top of the customer's Transaction List depending on when you recorded them. It can be from oldest to newest or vice-versa (with or without memos). You can click the Date icon to switch them in between those two periods. 

First, let's go to the Audit Log to see if your invoices and their associated payments (with memos) are the oldest or most recent ones. If yes, we're unable to arrange them. If no, the browser's stored cache may be full. Then, perform the steps below to help fix this. 

I'd suggest logging into your QuickBooks Online (QBO) account via an incognito window. It doesn't store data in the cache, so it's a great way to isolate browser-related issues. Here are the keyboard shortcuts: 

• Mozilla Firefox or Microsoft Edge: CTRL + Shift + P
• Google Chrome: CTRL + Shift + N
• Safari: Command + Shift + N

From there, go back to the customer's Transaction List. If it works, let's clear your browser's cache to have a clean slate, so it'll function efficiently. If not, use other supported web engines to get the best and most secure experience with QBO. 

Aside from viewing the Memo column in the said list, you can edit, copy, delete, void, send, or print your customer transactions. Doing this will help ensure their balances are up to date in QBO. 

Also, I recommend running the Invoices and Received Payments report to view the invoices and their associated payments within a specific period. Just go to the Reports menu and locate it under the Who owes you section (see the screenshot below). 

Leave a comment below if you have follow-up concerns regarding customer transactions or other inquiries. I'll be around to help. Keep safe.