Can and will my Master Agent (American Wireless) file lawsuit on me?

I am a small business owner and I am on the verge of dissolving it (its an LLC). I sell phones for a Master Agent called American Wireless and they are now telling me I owe them somewhere near $100,000. The problem is I dont have anywhere close to that kind of money to give them and they have shut down my operations by not letting me order anymore phones and holding my commission checks. So how can they just say I owe them this and shut me down? They say I owe them this for chargebacks, which are chargebacks on commissions when the customer doesn't keep their phone or pay their bill for 120 days. My father is the personal garuntor on the account and I so worried that I am going to ruin his credit completely if I dissolve the company. SOMEONE PLEASE HELP!!! Does anyone know what will happen? Will they file suit against my father? Collections? Can they take anything?