Fake bill and threatning calls from Legal department

I have a post paid connecting from Vodafone,I use this phone as an alternative to receive personal calls however for the past few months I wasn’t using this phone it was lying in the cupboard in my house,no incoming nor out going still I get a bill of 2500 asking to pay when I asked the agent to give me the call history they failed to and started sending collection agents to my office and made threatening calls to me forcing me to make the payment,I repeatedly asked for the bill details as to how they were billing me and they said tat some services were on it which I never ever activated.this company is fooling people by doing this kind of things,they are activating services with the customers knowledge and sending heavy bills where as the monthly plan was only Rs 199.
Action should be taken by the government to stop such harassment to customers.
Vodafone sucks!