@Panki As a first step, u should check with their bank to see if they have received the refund/unblocking instruction.
If there is no problem with the bank, contact the Registrar.
Contact the Registrar online by sending an email OR visit the nearest branch of the Registrar.
If no resolution is found, contact SEBI as a last resort.
File an IPO refund complaint with SEBI on the SCORES website or send a physical application/complaint request to SEBI.
Contact SEBI's Toll-free Helpline desk for Investors on 1800 266 7575 or 1800 22 7575 for any guidance/status update/queries.