My balance was deducted unfairly

Location/place: Mumbai

Name of company/service: Vodafone

I recharged for net pack today and i received message stating that my plan was activated after that i started using internet from my mobile.after sometime they unfairly deducted 324/- from my balance at rate 10p/10kb.when i called customer care they said that the plan starts after 3 hrs.I was not informed this in any message and if it plan was going to start after 3 hrs why did they send activation message..?..