Any person, group of individuals, partnership, limited liability company, corporation, or employer which acquires the organization, trade, or business or substantially all the assets thereof of an employer shall notify the commissioner thereof in writing by registered or certified mail not later than five days prior to the acquisition. Unless such notice is given such acquisition shall be void as against the commissioner if, at the time of the acquisition, any combined tax is due and unpaid by the previous employer. The commissioner shall have the right to proceed against such person, group of individuals, partnership, limited liability company, corporation, or employer and the assets so acquired.