I haven't even receive the Doro. I don't even know who to contact. I try 80 and he actually replied once. Then he went silent afterwards.
Same here. At this point I'd prefer my money back since this group buy has been a mess. I'd at least like my keyboard if that isn't an option, though.
Hopefully your invoice isn't more than 6 months old.
The GB was run last year. Just checked, my invoice was dated 9/7/2018, more than a year old. 
I would hate to write off the loss, because that's $400 we're talking about here. But I simply don't know what else I can do when I keep emailing 80 and he does not respond.
Some people "refreshed" the invoice about 6 months ago, e.g. when the first 6 months were going to expire, asked a refund and paid a new invoice which is a total new invoice, probably he didn't.
Everyone should ask for a refund if the keeb doesn't arrive before the 6 months mark and eventually pay a new invoice, because there is always a risk involved in any GB.
I'm afraid to say, if 80 doesn't answer/send (i doubt at this point), there is nothing you and the other guy can do over than just waiting.
I would suggest to contact paypal anyway, NOT because they will help you (they can't after the 6 months mark), but because they can eventually flag/report his account/bank account if enough reports are issued (that's what i suppose, regarding your money guys pp can't do anything). Sorry
