Pune Resident Asks: 'How to Use Excess Self-Assessment Tax Paid Twice in Previous Year?'

Sir, While filing the return for AY 2024-25, I had, by mistake, paid the balance of tax amount and TDS i.e. Self-Assessment Tax twice through online procedure. Both these amounts appeared in AIS under different BSR Codes and challan numbers on the same date. In the return, obviously, only one of the amounts had been entered and hence only one of the amounts was accounted for in the tax calculations while the other amount remained unaccounted, though appearing in AIS. The return has been duly processed under 143 (1) with no demand- no refund. Now, the question is- how can the unaccounted and unused amount appearing in AIS for AY 2024-25 shown as Self-Assessment Tax can be utilised for the next AY, viz 2025-26 as Advance Tax? What procedure should be followed? Alternatively, can this unused amount be claimed as a refund, through a revised return showing both these amounts or a rectification return would be appropriate? Shall be grateful if you kindly guide me as to how to do this. R M Khatsuria, Pune