Vodafone — sim card expired

Address:

Bathinda, Punjab, 151004

I am using my vodafone number since 2014 and its expiry date was in the year 2021. Last week they sent me a message to recharge my number with rs 35 in order to continue my services. I made a call to the customer care and they said they are having some technical issues and also assured me that my number wont expire. Next day my number expired. Once again i called the customer care and asked them that my validity for the sim was till year 2021 and now they have reduced the validity all of a sudden from 2021 to 17 nov 2018 and also have stopped all the outgoing services [calls, msg, data]. They say this is as per the trai rules and now i'll have to recharge my number every month or after every 84 days.
This number was never left unused and i use this number everywhere. I am using this number regularly [ both for incoming and outgoing ]. How can they change the expiry date all of a sudden and discontinue my services and force me to recharge it every month!

Please guide me

Thank you