Any person who is required to precollect or pay a tax as established in this chapter and who fails to precollect or remit the tax or any part thereof is fully responsible for the unpaid tax. The director may recover any unpaid taxes pursuant to this chapter from any party who was under a duty to precollect or pay the tax. Such person remains liable for the taxes even in the event that, for whatever reason, such person failed to precollect or pay the taxes due. The liability to precollect and remit shall be separate from any duty that the consumer may have pursuant to this chapter to pay upon consumption, and the existence of such overlapping duties shall not be a defense for a failure to precollect and remit, though it may give rise to a refund claim in accordance with section 142.824 if both parties pay the tax.