Point of order, the former client has a plan, not you. Usually in wrapping up a corporation, final actions include appointing an officer to wrap up its affairs in an orderly manner. Who was named to do so? Also, who were the trustees? Do they want an IRS/DOL non-filing inquiry in a couple of years? Who will respond to it and what will they say? If they don't response, they may get an investigation. At that point sucks to be them, running up lawyer fees with no plan or corp to pay. Their choice.