PPF — Interest payment

Address:

3,FIRST TRUST MAIN ROAD, Chennai-600028

PPF A/C with Post Office, R.A.Puram, Chennai 600028
I had opened PPF a/c in he name of S.Sankaran H.U.F . After 15 years, it was extended for 5 years from[protected]. I have been depositing since then till 2-7 2000 every year.
In December 2020, they told me to close the account as PPF in HUF name can not be extended. Accordingly, I closed the account. But to my surprise, they reversed the interest credited during from 2016 to-date totalling Rs. 233782 including interest on accumulated balance for the first 15 years.
As the a/c was extended by P.O, I have been depositing the moneys in good faith. For no fault of mine, I am deprived of interest on the moneys held by them.
I, being a retired person, seek remedy for recreding interst, wrongly reversed by P.O.