Singapore cancels student ID card

You can't ignore your old school, because the school can contact the Immigration Bureau and unilaterally cancel your student ID card.

You need to communicate with the school and explain your current situation. If not, ask the school if you can apply for a temporary residence permit such as a temporary tourist visa.

Finally, if the school is really such a dog, it can only apply for a tourist visa by itself.

I hope my answer can help you.