India Post — 10 Rupee coins not accepted by Post Office Savings bank

Address:

Rasipuram S.O Salem Main Road, Rasipuram, Tamil Nadu 637408

Respected sir/Madam,
I am the customer of the Post Office Savings Bank. Today (13/08/2021) I went to bank to deposit 5000 Rupees in my account at Rasipuram S.O branch (637408). In which there are 25 number of 10 rupee coins were not accepted and refused to deposit it in my account by cashier.
When I asked the reason, the cashier said that we will not accept the 10 rupee coin and the 10 rupee coins are not circulating in a market. I said him that it is legally released by the RBI and a valid coin.
But still he refused to accept the coin and also he said that according to the act of coin 1873 these many number of coins not accepted at a time. You can complaint anywhere but i will not take these 10 rupee coins.
Kindly give me the guidelines about the 10 rupee coin and what is the maximum amount of coins that can be deposited at the bank and i also want the clear reason that why the bank is not accepting the 10 rupee coin, though the RBI says that the bank will accept the 10 rupee coin.