Infrastructure Development Finance Company Limited — Maturity amount not received on my bank account

I bought "IDFC 9% CUMM SR 2 BD 30DC21" on 30/12/2011, it's should mature by 30/12/2021, but so far i didn't received amount in my account or any communication from IDFC or kfintech, so far i wrote mails and provide details about my purchase of BOND, but they are answering me they don't have any details. My humble request please help small investor like us.

• Folio number / DP ID & Client ID :- IN[protected]
• PAN number:- AQRPP0170B
• RL No. 214810
• REFNO- 503514
• Application Number:[protected]