Vodafone — False billing and Replies to emails

Address:

Mumbai City, Maharashtra

I was using message pack of vodafone since six month which is auto renewable.
until last month everything was normal.
from last month they deactivated message pack from my account without notifying me prior and charged me for the messages.
when i emailed them my querry they told me my coorporate scheme was not eligible for message pack.
then how was i using it since past six month??
also they failed to take action in 72 hours as stated by them in email
i have the emails saved with me.