Can you answer a strange health insurance eligibility question?

My mother just called me in tears because her employer just notified her, via letter, that she was 8 hours short for the year. This means that she will be booted from the insurance plan shortly. She’s upset because she was never informed about the minimum or that she was under her minimum hours.

It could be argued that she should have monitored it or known that there was a minimum. But it’s done, and she’s now tasked with writing an appeal letter. Correction – she’s tasking me with writing this letter, or at least helping her.

Any suggestions re: what this appeal letter should contain? Can she simply claim ignorance? Make up some elaborate story about illness? Threaten legal action?

I have no idea who to even consult. Any suggestions would be helpful. Thanks.