We usually see this question when someone has just switched their account from Test mode to Live mode. When that happens, the default setting on the Transactions page switches to “Live” transactions.
To see your previously uploaded Test transactions, click on the the three vertical dots in the upper right corner. A window will open, as per the screenshot below. By default, the system always shows completed (Captured) Live transactions once your account is Live. To switch to the Test account view, just de-select the 'toggle switch' for "Show Live Transactions".
If that doesn't solve the problem, please contact us at firstname.lastname@example.org.