Flipkart — Not delivering the phone for availing BuyBack offer

I have placed my 5th order Order ID - OD[protected]
I placed almost 5 orders and all orders reach nearest hub but doesn't get to the point "Out for Delivery" stage. The delivery gets postpone for 2 more days and this is happening for all my mobile orders. The only reason is that i placed order with Buyback option availed for MI10t. I bought this phone with Buyback option and now i am trying to exchange this phone with new phone buy paying difference amount. The flipkart customer service is not at all bothered about the issue and disconnected my call in confusion. When I reached the nearest hub, they clearly say that its Flipkart issue and they are getting problem in "Runsheet", i said the same to 15 customer service agents and nobody is figuring out whats the issue. This is my last order i am placing and it is also stuck in nearest hub and can't be delievered.