Need to get the Tracking Number Barcode

Hi,

I have a customer who claims that he didn't receive an item he bought from my dropshipping site.
I checked the tracking info and it said that the item was delivered to his mailbox.

When I sent him the details he contacted his post office and they asked him for the "barcode".

I don't have the barcode of course and it seems the seller on Aliexpress doesn't understand what I'm looking for.

Is there any website/way/method to enter the tracking number and you get the barcode generated?