IISER Kolkata - URGENT pre-registration refund

i had been mailing iiser kolkata from last ** days to resolve my problem of the pre-registration refund, but no one is replying.
the landline numbers specified in the website are irresponsive. once, fortunately, a lady staff picked up and i told her my problems, she said she will forward my request to concerned authority and they will give you the solution by mail. it had been one week from that call i have got no email.
now again the landline numbers are not being picked up by anyone.
if my complaint against iiser kolkata will not be considered serious then i'd have no choice but to file an rti against iiser kolkata.
thank you.