I am missing one week of credit card transactions from the register. I matched these transactions to the expense category but they disappeared.

Hello there, mtrammco.

Thank you for posting here in the Community. I'm here to help locate these transactions in QuickBooks Online.

We can go to the Banking section and review the matched transactions through the In QuickBooks/Reviewed tab.

Here's how:

1. On the left panel, click Banking.
2. Go to the Banking tab.
3. Select the account.
4. Go to the Reviewed/In QuickBooks tab.
5. Search for the transactions you want to check.
6. Click to check the status below the Added or Matched column.
7. You click Undo if you want to make changes (it'll revert back to For Review tab).

I'm adding a sample screenshot for your reference on this:

Please know you can always come to the Community if you need further assistance with locating these transactions. You can reach out to me by posting a response below.