The binding legal principles established are: (1) A person employed "for a limited period" as defined in pension fund rules is employed for a fixed term, and a renewal clause in the employment contract does not alter this characterization at the time of purported admission to membership. (2) Where pension fund rules exclude a category of persons from membership, the admission of such a person is ultra vires and void, regardless of the fund's subjective belief about eligibility. (3) Estoppel and waiver cannot be invoked to validate conduct by a pension fund that is ultra vires its rules, as this would create an unlawful situation. (4) For purposes of section 1 of the Pension Funds Act, paragraph (d) of the definition of "complainant" ("any person who has an interest in a complaint") should be interpreted broadly to include any person with an interest in a grievance meeting the substantive requirements of the "complaint" definition, not only persons with an interest in an existing complaint lodged by someone else. (5) The admission of persons to membership and receipt of contributions constitute "administration" of a pension fund for purposes of the "complaint" definition, even when done unlawfully or ultra vires. (6) The Pension Fund Adjudicator has jurisdiction under section 30E(1)(a) of the Act to grant any relief that a court of law could grant, including relief based on unjustified enrichment. (7) Where contributions are paid to a pension fund in respect of a person who never legally became a member, the elements of the condictio indebiti are prima facie satisfied: the person making/authorizing the payments is impoverished, the fund is enriched by receiving money without legal cause, and the onus shifts to the fund to prove it was not enriched or only partially enriched.