I just had an Idea.
if it´s possible I would take it as a temporary solution at own risk

well, the idea is to identify player login and nickname.
no match = payout
match = no payout
I think this should work.
to the bad of ppl who even bought the game but are no able to set a nickname at least by making it coloured, they probabely don´t know how to spend planets or don´t even having the VALID CODE ^^