Ecom Express — Product not delivered and no response from customer service

My product was supposed to be delivered on 6th July, everytime I was getting message " Shipment undelivered cannot be delivered ". Now it's showing shipment RTO Lock. That means it's again returning back to origin. May I know what challenges were you facing during delivery. I couldn't found a single way to reach out to the CUSTOMER service. Amazon, flipkart, bluedart all those deliVERY COMPany can reach out at my address, what challenges did you faced????
This is so ridiculous. Stop doing business if you don't know how to support a valuable CUSTOMER.

I need my product ASAP, don't reply with ### comments. "We are sorry bla bla... "
I want the exact solution, that's it.

- Subhankar Dey