I am pretty sure I have been scammed by a user with zero reviews whom I traded with. Sent out cards 3 weeks ago so they most definitely should have received them by now but I have not received theirs. I would like to report them alongside a bad review. Is there any way to do so?

Hello,
 
Please open a litigation here :
https://en.pokechange.net/forum/section:cs14
 
And indicate the username and URL of the associated proposal.
 
Thanks,