You can check your Retail Outlet transaction in your Callback tab and resend it by following the below steps:

• Log in to your dashboard
• Go to Callback tab
• Set the filter product type to Over-the-counter paid 
• Filter the date with the paid date found in the payment proof to narrow down your search
• Fill in the search parameters with Product ID/Payment ID that can be retrieved from your system. it starts with pymt-

• Click the transaction and you will see the callback details. You can also click Resend if you want to resend the callback to your system.

• If you want to resend multiple callbacks, tick the transactions that you want to resend and click Resend

To know more about callbacks, please visit our reference here.