Undelivered parcel

I booked a parcel through Leopard Courier from Sialkot, but it was returned without being delivered properly. The receiver informed me that they receive hundreds of parcels daily and that the courier failed to complete the delivery correctly.
I have contacted Leopard Courier several times and filed multiple complaints, but my issue is still unresolved. No proper explanation or solution has been provided, despite having all the shipment details.
Due to Leopard Courier's negligence and poor customer service, I have suffered a financial loss of approximately PKR 12,000