WASHINGTON (WUSA9) -- It's one of the most lucrative ways pimps make money off the women they prostitute, and it's responsible for helping sell the bodies of 90% of the teen sex trafficking victims in our area. But, the website Backpage just got slapped with a crippling one-two punch. Both Mastercard and Visa say they will no longer do business with Backpage.

One source says Backpage makes $9 million a month from pimps placing sex ads. With both Visa and Mastercard no longer being able to be used to pay for ads, one non-profit that fights sex trafficking says it's like cutting off a major highway to the virtual street corner.

Andrea Powell is on Backpage every day, looking for souls to save. She runs Fair Girls, a D.C.-based non-profit dedicated to helping sex trafficking victims escape the life. She says 90% of the underage girls she helps were sold on Backpage.com. News of Visa and Mastercard closing the door to the site was a huge win for her and the girls.

"Pimps are now completely restricted and Backpage.com's business model is completely deconstructed."

Powell says most survivors she works with are first trafficked when they're between 12 and 14 years old, and many come from D.C., Maryland and Virginia, and some from affluent families. There are many.

Powell says she scrolls through 200 to 400 sex ads on the site a day. She says this development is major and a possible game-changer, since she and other advocates have been lobbying Backpage for years to stop helping pimp people.

"It's going to make it harder for pimps to do their business, it's going to make it harder for men to buy girls and it's going to create a new shift. Other companies are going to be watching and they're going to be pulling out as well."

American Express already stopped doing business with Backpage. One study says the site accounts for 70% of prostitution ads placed among the five websites that carry ads in the U.S..

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