"My first thought was, 'This didn't happen,' " he said of the moment he realised his mistake a few days after making the donation. "Then it was, 'How could this possibly happen?' "
Crowdfunding sites at their best carry the awe-inspiring power of bringing strangers together to help people at their most desperate hour: families who have become suddenly homeless, parents who find out their children have cancer, widows left with newborns.
I have personally seen it used to help a couple put presents under a Christmas tree for children who would have none to open otherwise and to help send a teenager to college after he graduated from a high school in Baltimore that saw three of its students killed in three months, including one who was stabbed in his heart in a classroom.
More recently, I saw it bring tears to a woman who feared she wouldn't be able to send money to her children in Sierra Leone after she was fired from her job pushing wheelchairs at Dulles International Airport because she was suspected of asking for a tip. The company that employed her has since done the right thing and rehired her, but when I first wrote about Isata Jalloh, she worried how she was going to pay her rent at an apartment and also keep her family housed in Sierra Leone.
That's the story that compelled Jim to donate.
It is also what led him to see a side of GoFundMe that most people don't.
The company apparently doesn't have customer service representatives; it has a "Customer Happiness Team".
A member from it contacted Jim after he wrote a desperate email on August 5 that explained his mistake and contained the words, "Please help!"
The reply read: "Thank you for contacting GoFundMe. We've received your message, and our Customer Happiness Team will respond shortly to assist you further."
Later that same day, an email arrived from "Mary."
"Not to worry," it read. "I'd love to get this sorted out for you."
She wrote that she had credited a tip that he had also mistakenly left for the company. "As for the $15,787 donation," she wrote, "it's not currently available in our system to refund right away."
She then listed his three options: "1: You can reach out to the campaign organizer to see if they can refund you directly . . . 2: You may be able to contact your bank or credit card company to dispute the charge for your donation . . . 3: I can personally reach out to the campaign organizer and issue the refund for you as soon as they reply with their confirmation."
And because she's a member of the Happiness Team, she signed it, "With Kindness".
Jim went with all three options. He emailed Isata Jalloh and hoped she would understand and give his money back. He contacted his credit card company, which informed him that he could only dispute the charges once they cleared, and so he waited a few days until they did. He also asked "Mary" to send an email.
Then days passed, and he heard nothing. He sent another email to the company to see whether there were any updates. There weren't.
"I realise that this was my error but this is an enormous amount of money for me so please don't give up on me," he wrote to a Happiness Team member a week after he had sent his first email. "I have already contacted the bank and I have no idea what else I can do. Do you have a contact phone number?"
"We do not offer phone support," came the reply, "but please know that a lack of phone support is not an indication of a lack of caring on our end. We just want to make sure that we're keeping track of our conversations, account details, and other specifics that would be lost in a phone conversation.
"As much as I wish that we could, we can't force the campaign organizer to respond to either our messages or yours."
What that Happiness Team member, and Jim, didn't know was that Isata was not ignoring their emails. She had no way of seeing them.
She doesn't have a computer or a smartphone. Before I wrote about her, and people started asking where they could send donations, she hadn't heard of GoFundMe. Someone helped her set up the account, walking her through each step, starting with creating a Facebook page for her.
Nine days after he first contacted GoFundMe, feeling no closer to a resolution, Jim wrote to me and explained what had happened. He described being moved to donate by the unfairness of Isata's firing and expressed his growing concern that he hadn't yet heard from her.
When I had last seen Isata, she hugged me tightly and cried when speaking about the generosity people had shown her. "They make me feel big," she had said. "I now have family here."
By then, the page had raised more than $45,000.
After hearing from Jim, I contacted the people who helped her set up the page and they arranged to meet with her and go through the emails. But first they had to find the time - and that wasn't easy. Isata spends 16 hours a day at the airport, working two jobs there, leaving her only eight hours to sleep and do everything else.
Then when they finally saw the emails, they realised the monumental effort that it was going to take to sift through them. More than 800 had been sent, all bearing similar subject lines. They didn't see the ones from Jim the first time they looked through the pile. Then they looked again on another day and finally found them.
Isata decided immediately that she wanted to return his money.
The people who were helping her contacted GoFundMe and described encountering frustration similar to what Jim experienced. They also couldn't get anyone on the phone. They dealt instead with several people through email who explained that the company couldn't accept a cheque from Isata and requested sensitive information that she didn't want to hand over to strangers: Her bank account number, bank statement and driver's license.
A spokesperson for GoFundMe, in an email, said mistakes with donations are "a rare occurrence but can happen".
"This is an extremely rare situation," the spokesperson said of the $15,787 situation, "and if a mistake, big or small, does occur, the donor will usually recognise it quickly and reach out to our Happiness team for assistance. We are working with the donor and the beneficiary to correct this issue and get the donor his money back."
In recent days, Jim said he has heard directly from the people helping Isata and he expects to soon receive a cheque with a large portion of the funds.
He retired from a software company and said he is still not sure how he made the slip-up. He suspects the explanation is as simple as he forgot to push the "tab" button after typing "15" and began filling out what he thought were other fields on the donation form.
In the more than four weeks that have passed since he made the mistake, he has made phone calls and sent emails trying to correct it while also managing, until a few days ago, to avoid alerting one person: his wife.
He worried that the stress would keep her up at night, and so it wasn't until Friday that he finally told her what had happened. By then, he was hopeful that the story would end as it had begun: with a person sending money to a stranger.