It would seem that if it could be proven that the “church” uses coercion to extract funds from their members they might stand a chance of prevailing. With Mormons, as with so many of the cults, your only hope to getting the ultimate prize is in giving major bucks to the organization - so, they use fear to threaten them with their very salvation (which they likely do not have at any rate unless they were led to the Lord earlier by a soul-winning, Bible-believing church where they were sealed for all eternity by the Holy Spirit. Yes, that is once saved-always saved.
Amen and congratulations on your exit and eternal life.