Max Life Insurance — increasing of premium wef 1st may 2009

sir,i have insurance policy no.[protected] with the [protected]@4000.48 per month on feb2005.company increase the premium by 1.03% on account of service tax as defined in finance act.1994 from may2009.this information given by company vide 20th oct,2009 letter on inquiring by me.now i want to know that on the date of policy award feb2005 the above act. was in force and company not mentioned in policy document like any type of change in premium.can company change the premium in the view of above mentioned act so later based its own desire. i have also three LIC policies 1986 to 1992 effective date but there is no change so far even act. enforce later 1994.