The Commissioner must not make a refund of tax to a person unless satisfied that the person –

(a) has not charged to, or recovered from, and is not likely to charge to, or recover from, any other person any amount in respect of the whole or any part of that tax; or

(b) having charged or recovered such an amount, is likely to reimburse, or take all reasonable steps to reimburse, each other person for the amount charged or recovered.