Delhivery - Pending return requests

This courier service has been putting off my crucial return requests even though the weather is decent and the pin code is serviceable. They keep giving reasons like the weather is poor and the pin code is unserviceable. A delivery partner literally came to my doorstep for a pickup, but refused after seeing the big box. He said they need prior intimation to pick up big boxes. Let me clarify that the box wasn’t even heavy and the product was an umbrella, so it had to be a big box. They have been providing no resolution to any of my complaints.