Minn. Stat. § 65B.161: REFUND OF PREMIUM ON CANCELLATION.

Cancellation of a policy of automobile insurance pursuant to sections 65B.15 and 65B.16 shall not be effective unless any unearned premium due the insured is returned to the insured with the notice of cancellation or is delivered or sent by mail to the insured so as to be received by the insured not later than the effective date of cancellation.