Zaaparel — no return or refund of the product

I bought a pair of black and white jeans from zaaparel which displays ads on instagram. I ordered size 34 but they delievered 28 and i asked for return and the delivery boy said he will ask them to get in touch but there was no contact number. I decided to email them but no reply on that as well and no refund has been provided. It was delivered by delihvery i asked them to help but no response from them as well.