California Code, Civil Code - CIV § 6810

(a) When an owner of a separate interest makes a payment toward an assessment, the owner may request a receipt and the association shall provide it. The receipt shall indicate the date of payment and the person who received it.

(b) The association shall provide a mailing address for overnight payment of assessments.

(c) An owner shall not be liable for any charges, interest, or costs of collection for an assessment payment that is asserted to be delinquent, if it is determined the assessment was paid on time to the association.