Service tax applicability on notice period unserved

At the time of Full & Final settlement with my ex employer, they have deducted some amount on account of recovery of shortfall period  ( I served only 1 out of 3 months notice period) and Service Tax @ 12.36% on the recovery amount. I wanted opinion whether service tax is also applicable on the notice period recovery. If not, then what is the remedy, can i claim it back a refund ?