Hello @vibronx.
Well, his lawyer just contacted me saying that I've to pay him 100€ for basically wasting his time and cause him damage and prejudice.
My experience on Fiverr was not good because of this (I know I could have done better) so I'll quit when this problem is solved... But thanks you a lot for your advises.
The only order I've delivered is a different one (this one was fast to make), and it's completed :).
The guy is saying that I've breached the contract... Is there any contract to break? Could he denounce saying that I have given him false hopes and wasted his time? There's no sense...
PD: The order is already cancelled thanks to the CS, but I wanted to cancel it because I've to make a lot of extra hours in my work (I'm indie game developer) so I had no time to work on Fiverr. I knew I was going to have to work so much overtime several days after I accepted the order. And I've explain this to the customer, but he got angry and started insulting me saying that I was a scoundrel and that I could shove my Trello up my a**.