Scammers are targeting parents desperate to find baby formula. Some have spent hundreds of dollars and received nothing.

• Needy parents say they're being scammed by people pretending to sell infant formula.
• Parents who spoke with Insider said they'd been conned out of hundreds of dollars.

When Marie Brennan was contacted on Facebook by a woman offering six cans of the infant formula she'd struggled to find for her baby on the shelves, she agreed to pay her $300.

The cost, including shipping, was about $14 more expensive per can than the price at the supermarket. But given the nationwide shortage of infant formula — caused by problems with the supply chain and the recall of some potentially contaminated brands — Brennan told Insider she was "desperate."

The seller seemed legitimate enough, with more than 600 Facebook friends and photos of a woman with kids on the profile. The person said they were a manager at a Walmart in Ohio and had access to formula as soon as the consignments were delivered to their store.

Brennan, who needed the formula for Annabel, her 22-month-old baby with specific dietary requirements, sent the fee by Venmo. Then she waited — and waited.

The formula never arrived.

At first, the seller claimed they'd sent the package days earlier and the Postal Service was to blame, Brennan said. But after two weeks, the person blocked Brennan on Facebook. The 38-year-old realized she'd been scammed.

Parents are ordering formula that doesn't exist

"I was upset and angry," said the mom of two from Valley Cottage, New York, who is about to deliver her third child. "It's added to the stress of my pregnancy, and my husband calls these people 'robbing bastards.'"

Brennan, who met the scammer on the public Facebook group "The Infant Formula Shortage Group," whose 2,500 members are supposed to assist each other through the crisis, said she reported the "seller" to the platform's administrators.

The person was added to a list of more than 350 people believed to have targeted moms in the group, according to Brennan.

Meanwhile, NBC News reported that infant formula was being traded on websites like eBay, Craigslist, Amazon, and Facebook Marketplace with a markup of up to 300%.

Authorities are trying to clamp down on the fraudsters and price gougers

The situation is so serious that the US Federal Trade Commission said it was investigating the possibility of fraud and price gouging as opportunists take advantage of the formula shortage.

In a statement, the commission's chair, Lina Khan, said her agency would "fully enforce the law against anyone who deceives, exploits, or scams" families wanting to purchase formula to feed their kids.

Brennan is pessimistic about the chances of her scammer being caught.

"I feel as if I can't trust anyone," she said. She added that feeding Annabel felt like "trial and error" because regular milk "curdles in her stomach." Most types of solid food make her vomit, too, she said.

Lyn Murphy of Swedesboro, New Jersey, said her 4-month-old daughter, Hadlee, had a sensitive stomach that could tolerate only a certain type of formula.

The brand is particularly hard to find, so when Murphy, 35, was down to just a few bottles, she clicked on a website that said it was in stock.

She spent $200 on the ready-mix formula but was horrified when it never showed up, she said. The site ignored her appeals, but since she'd paid by credit card, she was able to recoup the cost through her bank.

Murphy said she was "so scared" about Hadlee not getting the right nutrition that she took the risk again. A person — who again had pictures of kids on the Facebook page — responded to a plea Murphy made on the forum, she said. The mom of three said she sent the seller $135 through Venmo before asking for a tracking number for the package. She received neither the number nor the formula.

"It's horrible," Murphy, who was later blocked by the person she paid, told Insider. "I've been spending so much money trying to get hold of this stuff, but I'm going broke."

There are still stories of kindness

Nevertheless, the strength of human kindness has helped Murphy cope. Members of the support group read her post about the scams and sent bottles of formula they'd located. "I'm very grateful," Murphy said.

Similarly, Clara Green, 35, of Atlanta was overwhelmed when her family and friends banded together to comb the city for formula for her 8-month-old daughter, Baeza.

The mom described the shortage as sad and depressing but said "parents taking care of each other" during the emergency was "beautiful to watch."