Amazon India - Wrong item delivered item was picked upon approval but refund not initiated

Order id :***-*******-******
I have recieved a wrong item from Amazon as on date ** th may immediately called them and informed them they asked for pictures and after sending all this they confirmed the return saying i will get my refund after pick up and in * th June my item was picked up and then I was told i will get my refund on ** th June but on ** th June they have send me a message saying they will not process my refund as the product doesn't match so they kept the wrong product also now they are threatening me and disconnecting my call please help me to get my amount back .
They kept the wrong product also and also my money and also the product that was supposed to me delivered to me .