I lost my inheritance to the doomsday prophet!

Eileen Heuwetter was shocked to find out that her deceased aunt left nearly her entire estate to Family Radio, the group behind predictions that the world would end May on 21.

NEW YORK (CNNMoney) -- When the world didn't end on May 21, many people who had given up their earthly possessions were left with nothing.

But one believer never lived to see the day. She left nearly her entire estate -- around $300,000 -- to the group behind the failed prediction, leaving some family members out in the cold.

Eileen Heuwetter was shocked to find out that her aunt left the majority of her estate to Family Radio, the group responsible for the doomsday warnings that the world would end on May 21. She and her sister were each left $25,000 from their aunt's estate. The rest is going to Family Radio.

The network of Christian radio stations based in Oakland, Ca., is almost entirely funded by donations. According to IRS filings, the group brought in $18 million in contributions in 2009 alone.

Heuwetter, the executor of the will, knew how much her aunt loved the radio station and admired its leader, Harold Camping, who is viewed as a prophet by many of his followers.

While other family members insisted it was crazy to let her aunt give all that money to a radio station, Heuwetter didn't initially contest the conditions of the will. She knew little about the Christian radio station, but knew her aunt, Doris Schmitt, found comfort in it.

Schmitt had lived a tough life, struggling with alcoholism and losing her two children to drug addictions before dying alone at 78 on May 2, 2010 in her small home in Queens, New York.

"This was not a woman who had anything. She literally had Family Radio on day and night -- she went to bed with it and woke up to it," said Heuwetter. "That was all she had."

It wasn't until recently that Heuwetter learned who was really getting her aunt's bequest. She said she first realized this was the same group when she saw buses driving around New York City the weekend before the supposed end of the world, spreading the doomsday message.

"I'm looking at these brand new buses drive around with Family Radio's name on them, saying 'Doomsday is May 21', and I said, 'Oh my god, this is who my aunt gave all of her money to," Heuwetter said. "I didn't know he was so crazy, and at this point I was incensed that this man was going to get everything my aunt had left."

While Heuwetter says she didn't necessarily need the extra cash, other family members were struggling and could have used a little help, she said.

Even worse, Heuwetter said, was that Camping's prediction never came to fruition. Heuwetter's family members were just as angry when they learned about Family Radio's failed prophecy, so they brought the case to several lawyers, who sympathized with the family, but agreed they had no case.

Family Radio did not respond to requests for comment.

The estate is within weeks of closing, and Heuwetter knows it's a lost cause.

"It's just so frustrating because I know there's nothing I can do about it -- this man is going to get hundreds of thousands of dollars from my aunt," she said. "And she wasn't a rich woman."

Doomsday church: Still open for business

Though Camping later clarified that his prediction actually extends until October, many followers were disappointed when the rapture didn't happen on May 21. Heuwetter said there is no way her aunt would have given the money to Family Radio, had she lived to see Camping's doomsday-gone-wrong.

"She would have been devastated," Heuwetter said. "Listening to him say things would be better in paradise made her feel better -- she totally believed she would leave this world on May 21, and she needed to believe that."

If she were here to watch the world continue after May 21, she would have likely given her money to other family members, said Heuwetter.

"It was a good amount of money that would have helped a lot of people live better today -- but now it's not helping anyone."

--CNNMoney staff reporter Annalyn Censky contributed to this report.