Is tax refund/adjustment claim on postal shipments possible?

Sometimes, on parcels delivered through Pakistan Post, the postman charges customs duty and hands over a receipt after payment. The charged amount includes custom duty, additional duty, sales tax, additional sales tax, withholding tax.

Anyone know if the WHT or any other amount can be refunded and/or adjusted in annual tax return for tax filer?

Well, technically we can claim the advance income tax part of it in our tax returns. The problem is, they do not give us the supporting evidence. The receipt the postman gives, usually contains a single amount (at least that is the practice here). I once went to the CED section of the post office where they held a tablet I ordered online. I had to provide invoice amounting to around $100, on which they charged me about PKR 5,000/- as duty+taxes, and it did contain advance income tax as well, but they did not give me a breakup on the receipt. Instead they offered that I could take a snapshot of their register in which the breakup was given, but that was practically useless because the register was about A3 size and the picture was of poor quality and could not be submitted as evidence. So I decided not to claim it.