Brother I would suggest to visit the concerned post office in-person, and talk with the concerned person, and may be, also with the Post Master of that post office.
In the mean time, you can also raise your voice on their help line No. and lodge complain. I think, complaints through email, website, etc. may not be that effective. Pakistan Post is currently at not that level of advancement / customer care, etc.
Still, if no one listens, lodge your complain on PM Citizen's portal. It wll definitely get resolved there.
I hope, it helps. Thank you.