On one hand schools are really strapped for cash, particularly state ones.
Wages take a vast proportion of the money that comes into the school. The amount depends, largely on the number of children on role. Their numbers drop a bit - but not enough to loose a teacher - this can cause quite significant financial problems.
As a former governor my school could be fine one year, financially solvent, the next year, a few children down, an unexpected repair, cost of living wage increases coming out of the unchanged pot and you are in trouble, can’t balance the budget.
Years ago the school were I taught had a termly ‘school fund’. Nothing like this sort of figure, even allowing for inflation. As a form tutoring I was expected to collect this in. I did about 75% of it but never got onto nagging and there were no notes sent home etc.
I never paid it myself when my own children were there, I reckoned I was putting more in buying equipment, materials etc and not claiming.
Later, possibly due to my colleagues lack of pushiness(?), they went onto 7 year direct debit tax friendly payments. Pupils were only there for 5 years and so you’d cancel after 5 years. (They hoped you’d forget!)
So as it’s voluntary I’d sit quietly, you’ll definitely not be alone in not paying.