Trustees of the old primary school in Rathmell, near Settle in North Yorkshire, are fighting attempts by the Diocese of Leeds to take ownership of the site, which dates back to 1716.
The school was turned into a community building, run by the Rathmell School Trust, after it closed due to dwindling pupil numbers seven years ago.
It has since been renamed Rathmell Old School and is used for activities, classes and community events.
The title deeds are registered to the trust, but the diocese is trying to take over the building using legislation which allows religious authorities to stake a claim for former church-run schools.
Trustees fear it will be flattened if the action succeeds.
The dispute is set for a costly High Court hearing in April.
Trustee Keith Mothersdale said the Church's attempts were "unchristian".
"I've been a Christian all my life, and I am ashamed to be a Christian," he said.
"If this is Christianity, forget it, [I] don't want to know. This is cruel."
The school became voluntary-aided – run by the Church in conjunction with the local authority – in the 1950s, before it closed in 2017.
Provisions in the Education Act allow the Church to seek ownership of a school site if a trust has "failed" – if a school closes or is no longer used for educational purposes.
The three trustees dispute that the buildings were ever part of an agreement for the diocese to take on the running of the school, as there was never any mention of a religious affiliation when the estate was originally left to the trust.
Mr Mothersdale said the group had racked up around £60,000 in legal fees since the Church made its original application in 2018.
"It's beyond comprehension," he said. "I'm on anti-depressants, you don't sleep at night, you're thinking about it all the time, but we can't stop, we have to do what we believe is right."
An online fundraising page to support the legal action has raised more than £9,700 so far, but the group says it could face up to £250,000 in costs.
The fundraising page suggests the Diocese of Leeds would "undoubtedly" sell the site for redevelopment, meaning the village would lose the "only community space" left in Rathmell.
Trustee Jacky Frankland said: "[I'm] astonished that an organisation that we're supposed to trust and respect can trample over people like us just trying to do a good thing for our community for their benefit."
She said the loss would be "enormous beyond words" if the Church won.
"They're doing this against the three of us personally," she said.
Local resident Joan Procter said the centre was "well-used".
"We need the facility," she said. "With good light, easy access, parking - it's ideal. And what'll happen to it if it doesn't stay?
"Once it's gone it's gone, it'll never come back, will it?"
The third trustee, Rosemary Hyslop, said it would be "so sad" if the village lost the heritage and history that the old school represents.
"We've basically got no amenities in this village, we've no shop, garage, post office, garage - we haven't even got streetlights.
"There's only 309 of us live here, but even so, why should we be deprived of our community centre?"
A spokesperson for the Diocese of Leeds said: “Numerous attempts to resolve this matter have been met with antagonism and so, regrettably, the diocese has been left with no option but to seek clarification in law.
"This will ensure the issues are fully considered and any proof provided.
"As this legal process is underway, it is not appropriate to comment further at this stage.”