Myntra.com — wrong colour and size received

Address:

Cuttack, Odisha, 753004

I ordered for jack and jones 38 size jean blue size but received 28 size jean yellow colour of jack and jones. Despite of frequent calls to customer care and sending emails no respite i am getting. I have requested for exchange since 30.12.2017. Tha delivery boy didnot pickup and exchange my 38 size jack and jones citing reasons as corresponding pickup item was rejected. I have already paid the cost. Now what should i do