Section 176A. An insurance agent or broker or premium finance agency who has received a return premium on any motor vehicle insurance policy shall within thirty days thereof pay over the full amount of said return premium to the person whose insurance policy has been cancelled or to his assignee, unless such person is otherwise indebted to said insurance agent, broker, or premium finance agency in which case any such return premium may be applied to such indebtedness and said agent, broker, or premium finance agency shall be required to pay over that portion only of said return premium which exceeds said indebtedness. In the event of payment to the assignee, notice thereof shall be given immediately to the person whose insurance policy has been cancelled. Failure by any agent, broker, or premium finance agency to return the full amount of said return premium or to give notice to the person whose insurance policy has been cancelled shall be sufficient cause in the case of an insurance agent or broker for the commissioner to suspend or revoke all licenses that may have been issued to said agent or broker, and in the case of a premium finance agency for the insurance commissioner to notify the commissioner of banks of the violation of this section.