Bata India — incorrect product sent and no response from customer service about returns

This is with regard to my purchase on the bata website for the following:
Order id is os[protected]
Invoice no: c[protected]

I had placed an order for a size 4 but the delivery made was for a size 6. Have tried calling them repeatedly and even sent an email but there has been no response. The shoe cost me rs.5000 so it isn't exactly cheap.

Thank you.