Info products and orders:

If you have already made a purchase and would like to receive further information, you can contact the seller from the purchased product page or from the seller profile page.

For technical problems with the site:

For any info or problem regarding the website and its operation you can communicate it to us via the service contact us by selecting "Webmaster" as the message object

For problems with unsolved purchases with the seller:

For any unsolved problem regarding an order you have placed, you can notify us via the service contact us by selecting "Orders placed" as the subject message.
Or directly from your Account / History and Order Details.
Before sending the message, be sure to choose the one related to your problem from the drop-down menu (Subject Header) otherwise the message could be processed late or canceled.