Amazon India - Package not delivered

I have ordered a product Ugaoo Cocopeat Block for Garden ** Kg three times having * different order numbers. ( ***-*******-******* , ***-*******-******* , ***-*******-*******) in the month of September ****. After waiting for * months I didn't receive my order so I have ordered the same kind of product of another brand TrustBasket Set of * COCOPEAT Block *kg - and it arrived late but successfully delivered. ( ***-*******-*******) Assuming that they will deliver the order late but Today, It is ** August **** but till now I haven't received all these three orders/still undelivered having order id's ***-*******-******* , ***-*******-******* , ***-*******-*******. I have informed the same to customer Executive via chat support but he denied to resolve this issue and gave the false information that the orders have been delivered, when I asked for the proof of the person who accepted, delivered then they disconnected the chat. The truth is that our orders are still undelivered and showing the same in my system. I have paid online and now, they are not refunding my own money for all the above * undelivered orders that I haven't received till now. it has been so long but they are denying refunding. I have also mailed but didn't get any response. Being a Prime Member of Amazon for so long I didn't expect this kind of behavior from them.