You might be facing some customer’s FB name consist of special characteristics that make it difficult to search their order. Or, some customers change their FB name after placing the order which you cannot trace them.
Do you notice that you can track through the order number? Every order created will have a unique order number. You can filter the order number to find the order.
Where you can find the order number?
1) Payment link which will appear in the messenger when a customer request their shopping cart.
2) Customer’s summary
How to filter order number?
Admin Panel →Menu→All orders→ADD FILTER→Order number