Am I missing something in the auction? It says that it comes with the 7-pin to dual 3 pin xlr cable, but you said it didn't come with one? The auction doesn't say anything about it being modified either. Are you sure there aren't 7-pins on the mic? Maybe a couple are broken off and it just needs to be replaced/resoldered?
FWIW, I don't see this mic working properly if it was in fact modified to a 3 pin xlr connection.