Austin, Texas (CNN) -- For years, Connie and Daniel Roddy did all they could to support Livestrong, raising tens of thousands of dollars for the cancer charity founded by cyclist Lance Armstrong.
"It all started when Lance's first book came out," Connie Roddy said, referring to the 2001 publication of "It's Not About the Bike: My Journey Back to Life," which details Armstrong's bout with testicular cancer. "I read it cover to cover. I was just so taken by who he said he was."
The Roddys, who live in Santa Monica, California, say they initially gave $50,000 to the foundation. In 2003, Connie Roddy said, she helped organize an event for the foundation at a health club that raised an additional $150,000.
Now they want their money back.
"I feel we were really fooled. We were really hoodwinked," she said.
Their concern comes in the wake of last week's finding by the U.S. Anti-Doping Agency of "overwhelming" evidence that Armstrong was involved as a professional cyclist in "the most sophisticated, professionalized and successful doping program."
Armstrong stepped down as chairman of Livestrong this week and has lost endorsement deals with Nike and Anheuser-Busch.
The seven-time Tour de France winner, who never failed a drug test, has consistently denied the allegations.
Armstrong has not addressed the findings but has instead urged his supporters to continue fighting cancer.
"The mission absolutely must go on," he said Friday night at the organization's 15th anniversary celebration in Austin, Texas. "We will not be deterred. We will move forward, and we will continue to serve the 28 million people around the world that need us the most."
The sport's governing body, the International Cycling Union, has said it will respond Monday to the doping dossier compiled by the USADA amid calls for Armstrong to be stripped of his seven Tour de France titles. The International Olympic Committee also is reviewing the evidence and could revoke Armstrong's bronze medal from the 2000 Sydney Games.
But Dutch bank Rabobank was not awaiting any further review. It announced Friday that, after 17 years of sponsoring professional cycling teams, it will end its program at the end of the year.
"It is with pain in our heart, but for the bank this is an inevitable decision," said Bert Bruggink of Rabobank's managing board.
"We are no longer convinced that the international professional world of cycling can make this a clean and fair sport. We are not confident that this will change for the better in the foreseeable future."
Rabobank said it had previously seen elite cycling as a good fit with the company, its clients and its employees. But that has changed since the USADA report alleging doping by Armstrong and others.
Its decision drew a sharp response on Twitter from British cyclist David Millar, who rides for the Garmin-Sharp team: "Dear Rabobank, you were part of the problem. How dare you walk away from your young clean guys who are part of the solution. Sickening."
The bank's decision was a blow to the Rabobank cycling team, according to its general manager, Harold Knebel. But other sponsors are sticking by the team, which will try to rebuild under a new name, he said.
"This industry can only survive with big international firms, and the way the sponsors now are responding to this situation is certainly not good," Knebel said. "If we want to stay in cycling and grow cycling on the world scale, then something has to be done."
But criticism poured in from some of the charity's donors.
Former Livestrong donor Michael Birdsong of Salt Lake City is among them. "The charity was established and publicized and got their funds based on a fraud," he said.
Birdsong said he was attracted to the organization after his wife -- an avid cyclist -- was diagnosed with breast cancer in 1998, about the time Armstrong won his first Tour de France title.
"She found his story very inspiring," he said. "Before we read his book, she would work all day, go to radiation treatments and go riding because that made her feel good."
In 2007, the couple "became part of the public face of the foundation," said Birdsong, a software engineer. "I was one of the people who would answer questions from people to raise money."
Though he had long been aware of Armstrong's alleged drug use, he said he didn't believe it. "I was a huge Armstrong fan from 1999 to the time he retired; I would defend him from anyone."
But, as his involvement with Livestrong grew, "I started to ask what are they doing with all this money they are raising?"
The foundation's IRS filing last year reported more than $100 million in net assets or fund balances.
The organization spent $2.1 million in compensation to its seven highest-paid officers and three employees, according to the IRS form. No member of the board, whose members include CNN Chief Medical Correspondent Dr. Sanjay Gupta, was compensated, it said.
Now, Birdsong said, he feels disillusioned. "The whole thing is founded on a lie. The guy cheated, and he forced other people to cheat. I would like my money back. We donated under false pretenses."
Livestrong spokeswoman Katherine McLane responded Saturday by reassuring donors that the charity has always been dedicated to the highest standards of the nonprofit world.
"They chose to support not a single person, but a cause that benefits millions of people throughout the United States and throughout the world," McLane told CNN. "They put their trust in Livestrong, one of America's top-rated cancer charities, and we can assure them that their trust was not misplaced."
McLane said 82% of funds raised by the Lance Armstrong Foundation, the charity's official name, are devoted to programs and services that benefit survivors and their families.
Livestrong has actually seen an increase in donations and purchases from the its online store in recent weeks, McLane said. Purchases from the store, which sells Livestrong's trademark yellow wristbands, sports apparel and accessories, have doubled in the past three days, she said.
"It's something the foundation is incredibly grateful for, and we take that as a sign that people, even in troubled economic times, value the free services that Livestrong provides cancer survivors and their families."
Bob Kile of Kent, Washington, said he is unfazed by the Armstrong controversy. The 65-year-old throat cancer survivor he has no plans to remove the yellow bracelet that identifies him as a donor to the foundation.
"If Lance doped, that certainly takes away from his athletic wins," Kile said. "However, to survive what he did and come back at all is impressive. To come back and create good like he did with Livestrong is even better."
Actor Sean Penn expressed a similar view on Friday night, as he entered the Austin Convention Center for the anniversary event.
"Of course he remains an inspiration," Penn said in response to a reporter's question. "I think anybody who's looking with a very clear eye at this would find themselves very hypocritical to consider otherwise."
The editor-in-chief of Bicycling magazine, Peter Flax, told HLNTV.com that he thinks the scandal would have an effect in the short term but that people should understand that cycling has already made moves to clean up its act.
"The next year or two will be difficult and pivotal years for the sport. People need to understand that the sport is way cleaner than it used to be -- far cleaner and more transparent than most other elite sports," he said.
CNN's Tom Watkins, Laura Smith-Spark, Scott Zamost, Alex Thomas and Emanuella Grinberg, and HLN's Anna Lanfreschi contributed to this report.