The act of being scammed during the sale of a pinball machine. The seller either has no clue what the fuck they are talking about or knowingly sells you a machine that is either incomplete or suffers from major malfunctions not described in the sale.
Put simply, congtards is the bastardization of the word congrats. It has been used greatly on online forums, chans and irc channels. It's more often than not used in a sarcastic manner.