Its like belonging to the Klan. They don’t exclude you because you’re black or Catholic. . They exclude you because you aren’t a white and non-Catholic Christian (and a bunch of other issues).
None of that really matters though since there is a presumably valid contract in place. That removes the need to concern ones self with the religious aspect and deal with the contractual and financial aspect. That is so much simpler than arguing religion.
If they refuse to honor the contract and op can not find adequate and comparable facilities and in a time frame that would allow a reasonable time for advertising the change of venue, op propably has a suit to seek whatever his losses will be.
My question to the op;
is this community center a public or private facility?