"I had to sit in front of all our staff and say, 'I'm sorry, I've let you all down'," Heaslip recalls. "It was the single hardest day of my life. I told them they were all welcome to leave if they wanted, but we wouldn't be making payroll that month."
The staff stayed on and the firm's outlook began to improve only days later when high-profile Auckland investor Peter Huljich, whose family interests now own 31 per cent of Pushpay, arrived on the scene.
"We were so unprepared," says 34-year-old Heaslip, an accountant by trade who grew up in rural northwest Auckland. "Eliot was there in shorts and a T-shirt and flip-flops."
They may have been ill-prepared and casually dressed, but the meeting ended up saving Pushpay's bacon.
"[Huljich] went from complete stranger on the 5th or 6th of December to making a $2 million investment on the 24th," Heaslip says. "We were then able to pay all our staff. He really believed in what we were doing ... and he was very reasonable in that he still valued the company at $8 million, which was about what it was valued at when Doug invested."
Fast forward two-and-a-bit years and Pushpay - which listed on the NZAX in 2014, before moving up to the NZX main board last year - has become one of the hottest local technology stocks, with a market capitalisation of $527 million yesterday and more than 200 staff.
Heaslip and Crowther both come from Christian backgrounds and Pushpay's app is aimed largely at US churches, to help them gather donations.
In Pushpay's words, the technology provides a "five-second giving experience".
The firm makes money through monthly subscription fees, which range from US$100 at the low end, up to US$14,000. The company also takes a cut of the credit card fees it collects.
In November Pushpay announced that annualised transaction volumes passing through its system had cracked the $500 million mark.
The company's shares, which have gained about 30 per cent this year, hit a record $2.83 last week after Pushpay announced annualised committed monthly revenue (ACMR) in the six months to March 31 had more than doubled to $29.1 million.
The firm also said its target of $100 million in ACMR would be reached six months earlier than previously expected, at the end of February 2018.
ACMR is calculated by extrapolating revenue over the next 12 months, based on the latest month's takings, assuming no new business is acquired in that time.
Pushpay was touting itself as having a faster growth trajectory than Kiwi tech star Xero last year, after it lifted ACMR from $1 million to $10 million in less than 10 months.
As of the market's opening yesterday, Heaslip and Crowther's shareholdings were worth about $67 million and $64 million respectively, putting them well above the $50 million threshhold required to enter the National Business Review Rich List.
But is loss-making Pushpay, which raised $18 million by issuing shares to new and existing investors last year, really worth a cool half billion?
Heaslip, unsurprisingly, thinks so.
"The growth that Pushpay has experienced does support the share price," he says. "People are paying today for future cashflow on the basis that we're going to keep delivering growth."
There are 314,000 US churches with an average of more than 500 attendees each. Pushpay supplies its technology to just 3766 (roughly 1 per cent) of them at present, suggesting plenty of scope for future growth.
"We've got a US$1.6 billion revenue opportunity," says Heaslip.
He says 29-year-old Crowther, a former HRV salesman, got the idea for the Pushpay app while sitting in a church service.
"We asked ourselves, 'What if it was as easy to give to the church as buying a song on iTunes?'"
Heaslip mortgaged his home to raise the seed funding needed to get Pushpay off the ground. Crowther invested the cash he'd saved for a house deposit.
"We put in forty grand each to build the initial prototype," Heaslip says. "That was pretty much all the money we had together."
He admits that mortgaging the house was a tough subject to broach with his wife, Sarah, but she didn't take long to come around to the idea.
"My wife's pretty supportive, she was like, 'You're crazy, whatever'."
It wasn't the first time he'd spent a lot of cash on a business idea.
"While I was an accountant I ran a whole bunch of businesses and tried different things, never with any success."
Pushpay's first customer was Auckland's Life Church, and it wasn't long before the company had most of the big New Zealand churches signed up.
The big question was where to next, which wasn't hard to answer.
"New Zealand's not a churchified country, but every man and his dog goes to church in America," Heaslip says.
East Lake, a 7000-member church in San Diego, became the first US organisation to start using the app, in April 2013.
Since early 2014 the company has been headquartered in Seattle, where Heaslip is based. It also has an Auckland office.
For now, Pushpay is chasing growth rather than profit - it posted a $6.1 million loss for the six months ended September - but expects to reach break-even on a monthly cashflow basis next year.
The company is dipping its toes in the water of enterprise bill payments in New Zealand, and already has AMP and Watercare Services on board.
But Heaslip says the main focus remains the US faith sector.
"We today have four of the top 10 largest churches in America and they have US$100 million annual budgets," he says.
"They're big organisations."
Chris Heaslip
Age: 34
Grew up: In Kumeu, west Auckland, and attended Kaipara College in Helensville
Family: Two young children with wife Sarah
Work history: Has been an IRD investigator and KPMG tax consultant. Also ran his own accounting business
Education: BCom, accounting and marketing; graduate diploma in commerce, tax and commercial law; Masters in Tax (Hons)