Delhivery — Delaying Delivery

Address:

Kolkata, West Bengal

I ordered a pair shoes in flipkart on 13th Sept 2015. (Order ID OD[protected] which would be delivered on or before 21st Sept 2015. But till now the I have not received it. Status shows that the shoes will be delivered by Delhivery courier.( Tracking ID[protected]. When I am tracking it, it shows " undispatched due to shortage of man power". What the hell is that? Why flipkart use this type of courier company? When I will able to receive it?