Mark says for the last six years, he’s been waiting for two metal boxes containing $3.5 million in cash and $3 million in jewelry and diamonds to arrive from Nigeria. He says “Kelly Smith,” a woman he met on an online dating site, asked him to help her get the boxes to the United States and promised him he could split the fortune with her.

WATCH: Why Man’s Overseas Online ‘Girlfriend’ Said She Didn’t Want Him To Appear On "Dr. Phil"

Mark says he’s spent more than $750,000 to pay for stickers and custom fees to get the boxes in his possession – but they’ve never arrived. He says every time the shipper “Kelly” hired to help move the boxes tells him they are on their way, he then asks for more money to complete the transaction.

Mark’s friend, Cyndy, says she believes he is being scammed and that there are no boxes, no money and no jewels.

After Dr. Phil shows Mark that the emails he’s been exchanging with the “shipper” are not what they seem and that the paperwork he’s been sent is not legitimate, Mark admits that it’s possible he has been scammed.

WATCH: “Dr. Phil” Show Goes To Nigeria To Determine If Man Who Sent $750,000 To Help Woman Is Being Scammed

In the video above, Dr. Phil shows Mark two boxes similar to what he says “Kelly” shipped to him, and has him look inside. “We made up boxes that were similar to that because psychologically, I wanted you to have the closure of seeing these boxes,” Dr. Phil tells Mark.

“Thank you, that does help, 100 percent,” Mark says.

“Tell me 100 percent you know this is a scam and you are going to unplug from this,” Dr. Phil says to Mark.

“It’s a scam. I’m done, and thank you for that, Dr. Phil,” Mark says.

In the video above, Cyndy has a surprise for Mark. And, tune in Tuesday to see what happens after the show. Does Mark stick to his commitment to stop sending money? Check here to see where you can watch.