Central Seat Allocation Board [Csab] — refund of money

I had deposited rs 36500.00 towards fees for csab for my son nihal sahu whose jee no.[protected]. He had been alloted seat in the first round. But he had opted to "surrender and not to participate in the next round". I should have been refunded back the amount to my bank account. I had sent emails to csab for refund of money on dated 18.9.19, 30.9.19, 9.10.19, 24.10.19, 31.10.19, 28.11.19, 6.12.19, 21.12.19 and 6.2.20. But till date i had not received any amount nor received any communication from them for refund of money. Also i tried to contact their telephones but no one is responding to the calls.
Kindly look into the matter for immediate refund of the money.