Amazon India — Amazon didn't pickup the return goods and not providing proper information

We have ordered 'Elgi Ultra Perfect Plus' wet grinder. Amazon delivered the defect piece. We put return and exchange request immediately after 2 days of buying. Delivery guy came from Amazon and he brought another piece, at that time my husband went to outside he went for 5 min.I told the delivery guy to wait for 2 min so I will tell OTP. He got frustrated and immediately he throwed the old grinder inside house which I have given to him and he left. Immediately he put comment that customer is not available product is not ready.
Again we called customer care and asked for return and they scheduled return for next day. Another delivery guy came and he saw package and he told 'I didn't expected this much big package so I won't take this other guy will come'. Immediately he put comment on Amazon that 'Customer is not available and package is not ready for pickup'. How delivery guys can send false messages.
From that day onwards daily we are calling Amazon customer care and telling all the process for 1 hour and they are telling that they will schedule return but nothing they are doing from past 1 week.
We are frustrated with calling Amazon customer care daily one hour. Even everything we are explaining but there is no use. Not sure they will take return or not.