(a) The insurer shall notify each member of the amount of the assessment to be paid by written notice mailed to the address of the member last of record with the insurer. Failure of the member to receive the notice so mailed, within the time specified therein for the payment of the assessment or at all, shall be no defense in any action to collect assessment.
(b) If a member fails to pay the assessment within the period specified in the notice, which period shall not be less than 20 days after mailing, the insurer may institute suit to collect the same.