what i have learned from Rabbeim is that the struggles with money Jews have, isn’t because they have to pay yeshivah tuition, buy expensive esrogim and lulavim, mazos, shabbos food, frum clothing etc. All that money that we use for that, Hashem gives us is separate and isn’t included in our designated amount of money Hashem wishes to give us.
Tuition is NOT included. Even if Chinuch Habonim is, so much of tuition goes towards others, that it doesn’t count. This is a common fallacy that Frum Yiddin have, that it doesn’t make a difference what I do, Hashem will give me the same bottom line anyway. NOT TRUE. Hashem gives brocha based on what you do, but how much per input is Katzuv from Rosh Hashana (as per Rav Moshe Wolfson). (with exceptions for true Ba’allei Bitachon, like the Rambam). We (as torah yiddin) do not believe in predestination, even in financial matters
As for the OP, get out NOW. Homeschool your children and stop paying tuition. Or discuss the issue with the school administrator, and offer to keep your children in school for a discount, or you should pull them out. Tuition is not worth Shalom Bayis, for which even Hashem’s name is erased.