CNN  — 

Two New Jersey veterans say now-Congressman George Santos promised to raise funds for lifesaving surgery for one of their dogs in 2016, then became elusive and took off with the money.

Santos, the embattled freshman Republican, faces growing pressure to resign after he lied and misrepresented his educational, work and family history. Santos has admitted to “embellishing” his resume, but has maintained he is “not a criminal.”

Rich Osthoff, a US Navy veteran, told CNN his pit bull Sapphire began developing a tumor in 2015, and it continued to grow in 2016. Osthoff said he was homeless, living in a tent, at the time after losing his job and house.

Osthoff’s mentor and friend Michael Boll, founder of New Jersey Veterans Network, told CNN he took Osthoff under his wing as part of the charity’s mentorship program and tried to get help for his dog.

Boll said a mutual friend connected the two veterans with Santos, who told them Santos was frequently involved with helping and rescuing animals. Boll and Osthoff both knew Santos by the name Anthony Devolder, they said.

Santos set up a GoFundMe for Osthoff’s pit bull, Sapphire, Boll said. A post from the Facebook profile of George Devolder links to a GoFundMe raising surgery funds for the dog.

“Sapphire is a 10 year old red nose pit bull that has been keeping this man company, she dose [sic] not deserve to die because of this tumor, she deserves to be treated and cared for,” the Facebook post reads in part. “Will you help this baby and her daddy stay together for a few more years? Does he not deserve to have her? Let’s all come together to help this family of two stay healthy!” the post says.

The fundraiser eventually raised around $3,000, according to Boll.

But things went south after Osthoff tried to access the GoFundMe money, he said.

Santos became uncooperative, according to Osthoff and Boll – at first saying Osthoff needed to take his dog to a veterinary clinic of Santos’ choice, then claiming another clinic wouldn’t accept Santos’ form of payment.

“I had to jump through hoops and do everything his way,” Osthoff told CNN. “He was just totally, totally difficult. One obstacle after another.”

Text messages provided to CNN by Osthoff show his exchanges with Santos in 2016.

“Hey Anthony, Rich here. I was hoping to hear from you. Just checking whether you made contact with the vet,” Osthoff writes in one text to Santos, who was going by the name Anthony Devolder at the time. Santos replies that he “just called” Osthoff and he’s been “jumping through hoops.” He adds, “They are not as flexible as you said they were,” apparently speaking about the vet Osthoff referenced.

Santos also writes that a vet “had already ruled out the surgery without the ultrasound because based on his experience he thinks it’s very invasive,” but he tells Osthoff he will take the dog to a vet to get an ultrasound “to give you piece of mind.”

After Osthoff says, “I’m starting to feel liked [SIC] I was mined for my family and friends donations,” Santos tells him that, because his dog is not a candidate for surgery, “the funds are moved to the next animal in need and we will make sure we use of [SIC] resources to keep her comfortable!”

“I’m sick of being jerked around,” Osthoff says in another text, to which Santos replies in part,”Remember it is our credibility that got Gofundme them seves [SIC] to contribute!” He added, “We are with the highest standards of integrity.”

Santos tells Osthoff he won’t allow him to accompany his dog to the vet for the examination, and Osthoff rebuffs the plan, telling him, “I don’t know or trust you.” In their final text from 2016, Santos tries to convince him to pick up the dog, but Osthoff does not reply.

Osthoff said he accused Santos of running a bogus charity, and Santos became confrontational.

“He got so angry with me and he blew up and refused to give me the money and then just wouldn’t answer the calls anymore,” he said.

Santos told CNN in a statement Wednesday, “I have no clue what he’s talking about, and the crazy part is that anyone that knows me, knows I’d go to hell and back for a dog and especially a veteran.” He characterized the story, first reported by Patch.com, as “just more of the pile on effect.”

“I have dozens of people reaching out to me in support sharing their stories about their dogs and cats that I help save and rescue,” Santos added.

“Prove it. Show us,” Osthoff said Wednesday on CNN’s “Erin Burnett OutFront” in response to Santos. “He should show us if he has all these people that reach out to him and love what he does.”

In a statement to CNN, GoFundMe said it removed the fundraiser from its platform after receiving a report about it.

“When we received a report of an issue with this fundraiser in late 2016, our trust and safety team sought proof of the delivery of funds from the organizer. The organizer failed to respond, which led to the fundraiser being removed and the email associated with that account prohibited from further use on our platform. GoFundMe has a zero tolerance policy for misuse of our platform and cooperates with law enforcement investigations of those accused of wrongdoing.”

Boll tried to act as a mediator between the two, he said, with no luck.

“Anthony pretty much was unhappy with anything I was saying and was reluctant to even speak with me anymore,” Boll said.

Santos eventually stopped replying to messages from Boll and Osthoff, and Osthoff says he never received payment from the fundraiser.

Osthoff said his dog passed away about six months after his last contact with Santos.

His dog, Sapphire, “was my little savior,” he told CNN. “She kept me on this planet.”

Osthoff said he had to panhandle for the money to pay for her euthanization.

Osthoff said he contacted the police about his interactions with Santos but said “it didn’t go anywhere at all.”

Because Santos went by a different name when the two veterans were in contact with him, Osthoff said he didn’t know Anthony Devolder and George Santos were the same person until recently.

“In December I started seeing him on TV,” Osthoff told CNN. “I recognized his face, and it just turned my stomach when I saw him.”

“That he was now given a position where he affects thousands of people’s lives…it’s really disheartening to know that,” Boll said.

In text messages sent last week, Osthoff addresses Santos by his current name and writes, “Where’s my fundraising proceeds George?? You owe me plus interest.” Those messages went unanswered.

This story has been updated with additional reporting.

CNN’s Andrew Haag, Emily Bushey, Andrew Kaczynski, Don Lemon, Brian Rokus and Jack Forrest contributed to this report.