What is the ruling if the entire advance payment for two years is taken from the existing Nisab?

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If both advanced payments for two years are taken entirely from the existing Nisab, the Zakat for the first year is invalid if we hold that the owner cannot reclaim the advanced amount (treating it as lost wealth). This results in the Nisab being deficient. If the Nisab subsequently becomes complete, the new obligation year (Hawl) commences from the date of completion. The advance payment made previously, before the Nisab was fully constituted for the second period, is thus deemed invalid for that future year.