Must I re-pay the expiation with the money I previously paid before knowing the fatwa?

Paying the expiation for an oath in cash is a matter of ijtihad (independent reasoning). Abu Hanifa permitted it, while the majority disagreed. There is no blame on one who follows a scholar in matters of ijtihad, and what they have done is valid and sufficient, even if it later becomes clear to them that there is a stronger opinion. However, if the truth becomes clear to them, they must act upon it in the future. Therefore, paying the expiation for an oath in cash in the past is sufficient and does not need to be repeated, but it must be given as food in the future.