In the event the program is carried out as provided in section 4071 of this title, the Administrator shall be authorized to adjust and make payment of any claims for proved and approved losses covered by flood insurance, and upon the disallowance by the Administrator of any such claim, or upon the refusal of the claimant to accept the amount allowed upon any such claim, the claimant, within one year after the date of mailing of notice of disallowance or partial disallowance by the Administrator, may institute an action against the Administrator on such claim in the United States district court for the district in which the insured property or the major part thereof shall have been situated, and original exclusive jurisdiction is hereby conferred upon such court to hear and determine such action without regard to the amount in the controversy.