I believe that a moving company overcharged me from a move from OH to IL. The company is headquartered in PA. I have correspondence from the company stating that they will refund a portion of my money, but has yet to do so.
Additional information
I'd moved to OH in Aug 08, and back to IL in Dec 08. On my move to OH, I used a very reputable company and had 3900# of household goods. Moving back to IL, the "other" company said I had over 8000# of household goods.
You will need to sue the company in the proper jurisdiction; this may or may not be Illinois, depending on the contacts the company has with the state. Presuming you signed a contract with the company, that contract may limit suit to a specific venue.
Disclaimer: This answer is provided as a public service and as a general response to a general question, it is not meant, and should not be relied upon as specific legal advice, nor does it create an attorney-client relationship.