Asper notice dt 13th feb 2014 tamilnadu govt tnvat web site has given access to get c forms for prior period to DEC 2012
you can read the notice below
Backlog Online C Forms
The online request for Backlog C forms has been rolled out through the Commercial
Taxes Department’s website www.tnvat.gov.in for the use of mercantile public from
13/02/2014.
Dealers will be permitted to generate online forms for the period prior to October
2012 from 13/02/2014 onwards. It is opened for giving backlog C forms request
between 13/02/2014 to 16/02/2014 this month and from subsequent months it is
between 1st
-10th
of every month and restricted to maximum of 6 months from the
date of opening.