You are correct. The reality is whether it's worth it to you to pursue these deductions. Perhaps the DOL might be able to assist you.
Generally, the employer may not deduct from your paycheck unless you have previously agreed to the deduction in writing. You can file a claim with the Illinois Department of Labor and/or speak to an experienced employment attorney. Many of us, myself included, will provide a free consultation.
This answer is provided for informational purposes only and should not be relied on as legal advice. You should be aware that no attorney-client relationship is established through this answer and none will be established without a personal consultation and the signing of an engagement agreement.