Wendy Cato has had a security system in her Hephzibah home for about 10 years.

Back in April, she says a man showed up at her house to offer her a free upgrade.

“He told me he was with ADT. He knew that ADT had been out previously, the day before, to install a more powerful battery,” Cato said.

She says the man talked her into signing a new contract for monitoring and a new system.

A crew went out there to change the system. That’s when Cato realized something was wrong.

“He tells me, be sure to call the other provider, so you don’t get billed twice. He then got in his vehicle and left. And then I started thinking, why would I be billed twice?” Cato said.

It’s a scam that’s happening around the country. One that 20/20 uncovered earlier this year.

The salesmen make you think your signing a new contract with ADT, but what you’re actually doing is signing a new contract with another alarm company.

“If they are our customer and then there contract is replaced by another company they will get double billed until they get that situation worked out,” ADT General Counsel David Bleisch said.

The salesmen will actually drive up and down your street looking out for these ADT security signs, then they will knock on your door and tell you that you need an upgrade.

“The way you would know if it’s a legit ADT salesperson would be by contacting us, asking for their photo ID, contacting us to verify that person is who they say they are,” Bleisch said.

It’s advice that Cato wishes she had before she let a stranger into her home.

“He’s still going up and down my road to other homes,” Cato said.

She ended up getting her money back and ADT even installed a new system for her after the whole ordeal with the other company.

There are other similar scams out there involving cable and satellite providers, as well as cell phone companies.

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