The Better Business Bureau warns timeshare owners to be wary of offers to purchase their shares. (iStock)

With fewer people willing to purchase timeshares, scammers are going after desperate sellers using a guaranteed sale as bait.

Time-sharing is a form of ownership where a group of owners each have use of a property for a specified time. It’s most often used in marketing vacation homes.

When Duane Nickull got a call from a U.S.-based company offering to take a timeshare off his hands, the Vancouver man was delighted.

"She said, 'I have a buyer, they're ready to buy it right now and there's no risk to me,'" Nickull told CBC News.

The deal came with a catch, however, that sparked Nickull's suspicions. He'd have to send $1,950 to Timeshare Express Services in order to close the sale.

He was told if anything went wrong he'd get his money back.

That's when Nickull decided to do some homework. He researched the company, and others like it on the internet.

"You'll run into lots and lots of stories of people who had similar experiences, who actually did pay the money, and once you pay the money, you don't ever see or hear from them again," he said.

Nickull walked away from the deal without sending any money.

Company gets an 'F' rating

The Better Business Bureau said Timeshare Express Services of Delaware has an F rating, the lowest possible.

BBB spokesman Mark Fernandez says timeshare scams are on the rise.

'When you're sending it through a wiring service, that's just a one-way ticket to losing your money.'—Mark Fernandez, Better Business Bureau

"We're seeing [in] the timeshare market that sales have dropped in the past year, and more opportunities are coming out there for scammers to take advantage of the down market," he told CBC News.

He said anyone getting an unsolicited call about purchasing a timeshare should be wary. If they're asked to wire money they should consider the deal a scam.

"You never want to wire money to a stranger," he said. "So anytime anyone mentions paying an up-front fee and doing it through a wire money transfer service, that's ultimately going to be a tell-tale sign that that's a scammer. Because when you're sending it through a wiring service, that's just a one-way ticket to losing your money.

Fernandez says always check out the company you're dealing with, and always get the offer and its conditions in writing.