Publishers Clearing House Imposter

My Father has been getting stuff from Publishers Clearing House in the mail saying he is close to winning a prize and it is his last chance to enter in before they draw numbers to see who won or your number could be a winner and he keeps buying stuff from them and they keep on sending him ads saying this is your last chance to enter and he never has won anything and I would like to help stop the spam mail or at least let pch headquarters know that this is an ongoing problem with there sweepstakes

I keep receiving calls from scam artists claiming to be with Publishers Clearing House and that I have won a couple million dollars and a Mercedes Benz. They want me to pay $500 before they release my winnings.