Duck Delhivery - Messed up my leaving formalities

Was sending my stuff back to Mumbai from Pune using Delhivery. Scheduled delivery was like 2-3 days but these duckers delayed pickup by 2-3 days and even after that the shipment is sitting in their Pune warehouse for one week, these lowlifes aren't bothering to deliver it citing delay using unexpected reasons.

Because of this duckhousery , I am unable to get leaving letter from my old organisation. I am raising help tickets but all I am getting is automated responses. How do I escalate this? There is an option to cancel the order but I will lose the courier cost and they will prolly return my stuff after 1 month.

Never depend on Delhivery for critical shipments.