Myntra.com — Not accepting an exchange or return for a product

I had bought Mochi heels from Myntra which clearly mentioned “easy return and exchange within 14 days”. The heels are small for me and I want to exchange it for a bigger size. However, now myntra is not accepting an exchange for the product by saying service not available at this pincode and neither is it allowing me to return it for the same reason. The only option they are giving me is of self shipment which is not feasible for me as I want to exchange the product.