Capital gains tax savings account

I made a capital gain of Rs 60 lakhs from sale of my flat in FY 20 and purchased another flat in another city within 3 months. The payment of this new flat were to be made in installments, so I opened a capital gains account in SBI. However the bank issues demand draft only towards demand notes raised by the builder. It is not even allowing payments from this CG account for property registration. In these three years the CG savings account has accrued Rs 36000 in interest, income tax on which has been paid. The last installment has fallen due on 16 June '24, after which there will be about Rs 1 lakh balance in the CG account. How to settle/ close the CG account in SBI? Can the property registration charges be paid from the capital gains? Will the accrued interests be offset from the balance at the time of account closure? Since the payments for the property were made in installments, from which time/ event the 3 year holding period will be considered (a registration of the sale was done immediately on payment of first installment in March 2021)?