Prefix hijacking, how to prevent and fix currently

[Tarun Dua <lists () tarundua net>]

AS Number 43239
AS Name SPETSENERGO-AS SpetsEnergo Ltd.

Has started hijacking our IPv4 prefix, while this prefix was NOT in
production, it worries us that it was this easy for someone to hijack
it.

http://bgp.he.net/AS43239#_prefixes

103.20.212.0/22 <- This belongs to us.

103.238.232.0/22 KNS Techno Integrators Pvt. Ltd.
193.43.33.0/24 hydrocontrol S.C.R.L.
193.56.146.0/24 TRAPIL - Societe des Transports Petroliers par Pipeline

Where do we complain to get this fixed.

-Tarun
AS132420