pureboost.pt review: product received is not what I order

I would like to report the wrong mistake done by an online company www.pureboost.pt which mention that is powered by adidas, wich is not true. I received finally yesterday 2 pair of tennis that is not corresponding with my request. Further more they arrived through china. Order #44b638-343. I write to the seller saying that I do not want the money back but get the 2 pairs of tine's originally ordered both with size number 40 2/3. Same style but with two different colours.
Accordingly with policy of their site, when the mistake was done by them, We should send back everything and they assume the cost of the return.
We have 15 days to do that. They never reply to any of my e-mails. On the website they do not have any address send back the purchase, not even any e-mail address (only a box to write) and any telephone number to contact them. I ask for their contact and did not get any reply. All this seams to me an ambush.
The tennis arrived from China and is something that I also do not understand. I just need to have an address to send back the tennis and their cc in advance to charge the cost of the delivery which they assume and the guarantee that I will get what asked or the credit of my money. I paid € 125, 56. I do not know the original country of the website. Only that they have.pt on the end of the web address
Thank you.
Margarida Lopes