Can a former school refuse to provide withholding tax documents for tax claims in Thailand?

Hi there guys,

Apologies not visa related but still a very confusing topic.

A month or so ago I quit my job at a school and I went to the tax office and they said that I can claim tax back on what was deducted from my salary. The tax office only requires me to do the "withholding tax document" and for this I need documents from the previous school.

What I need to know is can that school legally refuse to give me the needed documents or do they have no choice to provide it to me?

Any other advice would be greatly appreciated.