Vodafone India — Plan changed without informing me and charged money

Address:	382480
Website:	www.vodafone.in

My number is : [protected]

My plan was rs around 299 and unlimited internet plan(1 GB-3G and later 64 Kbps) however they charged extra 650 rs of internet charges

When i visit vodafone customer care- they told me that your plan changed to 750 MB and then chargable which i am not even aware

they are cheating with customer and not informing. I dont want to change plan how can they change my plan?

Please do helpful

Thanks
Ranchhod