"Some serious lacunae in the written test were noticed and the interview panel found the results of the written test to be unsustainable. The recruitment agency confirmed the lacunae in majority of the cases". So the organization has decided to cancel the tests conducted and will hold re-examination to maintain purity in the recruitment process.
The Schedule for the re-examination will be announced soon. Check complete details from below link.
Check the cancellation notice released by GIC from here
Thanks to Pankaj Yadav for the update