For the last six years, Mark says he’s been sending money overseas to help his friend “Kelly Smith” get her million-dollar inheritance out of Nigeria. He estimates he’s spent about $750,000 on custom fees, “stickers” and documents to help “Kelly,” whom he met on a dating website, get two boxes filled with $3.5 million and $3 million in jewelry and diamonds back to the United States.

“I met ‘Kelly’ on She seemed really nice. She told me she was from Canada and she now lives in Nigeria,” Mark says. “Her father left her [the] deed to property in Nigeria worth about $3.5 million and goods worth $2 or $3 million.”

WATCH: Woman Fears Doctor Friend Has Been Scammed Out Of $1 Million By Fake Overseas Girlfriend

Mark’s friend, Cyndy, says she’s convinced Mark is being scammed. She says that he even asked her to send money when he was banned from using money transfer services.

Mark, who says at first he thought he was being scammed until “Kelly” reassured him that the inheritance was legitimate, says he sold his house, took money from his clinic and stopped paying taxes to help her, because he says “Kelly” promised him half of the inheritance.

WATCH: Woman Believes Friend Has Been Scammed Out Of $1 Million – So Why Is She Sending Money For Him?

Mark says he’s been working with a professional shipper that “Kelly” hired named Adeola, who is supposedly paying money to get the boxes through customs and sent to the U.S. Six years have passed, and the boxes have still not arrived in the United States – but Mark says he is still certain he is not being scammed.

In the video above, Mark tells Dr. Phil four reasons he says confirm to him that he is not being conned. And on Tuesday, the Dr. Phil show conducts a global investigation to determine where the boxes are. See what is discovered at the address that Mark gave for “Kelly” in Nigeria! Check here to see where you can watch.