It concerns us to hear that any Merchant may be using our services to sell infringing material, which would violate our Terms of Service as well. To satisfy legal due diligence, we would be glad to comply with a formal DMCA Notice demanding takedown of any material which infringes your copyright; please send that notice to our Support team:
https://www.e-junkie.com/ej/contact.php
You can find more info about DMCA Notice requirements here:
http://www.chillingeffects.org/dmca512/faq.cgi#QID130
Of course, as you say this is material that PayPal prohibits selling through their service, regardless of copyright matters. While we will be happy to comply with any formal DMCA Notice regarding materials which infringe your copyright, our service does nothing to disguise the seller's PayPal account anymore than PayPal's own purchase buttons would do for that account. If you haven't already done so, you can and should report the seller to PayPal, who should readily be able to determine the PayPal account being used to receive payment for those items, regardless of the seller using E-junkie buttons to take orders for them.