Job Withheld Pay After “at-will” Resignation

I recently resigned (two-week notice) from an at-will charter school in Arizona. Today (January 21st, the day I was supposed receive my paycheck) I received a letter dated January 17th stating my paycheck in $xx amount that I was to be paid tomorrow January 22nd will be withheld to cover liquidated damages in the amount of $5000 and that I have 60days to pay the remaining amount or legal action will be taken against me.

-I did not sign, agree to, or nowhere in my contract or employee handbook does it stay my paycheck will be withheld to cover liquidated damages from me resigning (again, this is an “at-will contract”. I did not receive prior written notice of this nor was this discussed, they just let me know the day I was supposed to get paid— hey, btw you’re not getting paid for the weeks you worked.) So they made me work KNOWING I would not get paid. -For the “liquidated damages clause”, it states that resigning MAY incur liquidated damages up to $5000. Doesn’t say “will”, “have to”, basically any legally binding language. -Another thing I feel is illegal is that it is strictly prohibited to share any information regarding salary without written consent from the CEO. From my understanding, this falls under worker conditions and is illegal?

Do I have any legal grounding here, or what should be my next step? Thank you!