Ask for a refund

Description

Hi,
I have recently purchased a product (paying via paypal) from https://www.etsy.com/.
I proceeded with the cancelation of that order.
However, the seller may not read my e-mail about the cancelation and he shipped the product (based on an e-mail I received).
Reading the reviews of that site I realized that it may be a site that cheats the customers (since they never receive their products neither get a refund)
and the sellers never reply to their emails (as in my case).
I would like to know how can I proceed in such a case since the seller does not reply to my messages and I want to cancel the order that I’ll probably never receive.
P.S. I have also sent a refund request to the seller without getting a reply.
Thank you in advance,
Maria Papadaki