CHICAGO (CBS) — They’re devout believers who donated more than $72,000 to a suburban megachurch, but years later they are disgusted and demanding a refund because of what they have learned.

Their strong Christian beliefs led Scott and Marsha Thompson to volunteer at Harvest Bible Chapel, and donate more than $72,000 over the course of several years.

Now, they want it back.

“We find out that the pastor is living in a $2 million house,” he said.

Pastor James MacDonald was fired last month for conduct “harmful to the best interests of the church.” He had been on “indefinite sabbatical” since January, amid allegations of financial mismanagement.

Thompson started questioning MacDonald’s spending in 2006, when he saw the pastor’s home in Inverness featured in “Chicago” magazine.

“You drive over there, and sure enough there’s the house that’s in the picture from the magazine article. Yep, that’s the house on a private lake,” Thompson said.

MacDonald’s lavish lifestyle drove Thompson to leave the church. McDonald no longer owns the house and hasn’t lived there in 5 years. Thompson walked away from Harvest in 2013. Why is he going public six years later?

“All this is coming out that millions of dollars potentially has been mishandled,” he said.

There are online articles with damning headlines, blogs listing litany of accusations against MacDonald, and then the bombshell when radio host Mancow Muller played audio and video recordings of MacDonald making what the church deemed “highly inappropriate” comments.

In the recordings, during which MacDonald obviously wasn’t aware he was talking on a hot mic, MacDonald made obscene jokes and talked about planting child pornography on the computer of “Christianity Today” magazine’s CEO.

Thompson called MacDonald’s recorded comments “sick” and “depraved.”

Since MacDonald already has been fired, Thompson wants the church to conduct a forensic audit.

Harvest church leaders wouldn’t talk on camera, but an update released this week revealed a “financial review” is underway. If they find something, Thompson wants MacDonald to repay the money.

“I want to see some justice,” he said.

CBS 2 could not reach MacDonald for comment.

Church elders are in the process of looking for a new pastor.