Vodafone — Post Paid- Legal Notice

I had a corporate post paid connection from Vodafone. When I accepted the connection I was told to submit a cancelled Cheque for Electronic Clearance Scheme. They lost the cheque and my Ecs was not activated. I again submitted a separate Cheque to get the ECS activated. They deducted a months bill from my account the next month. When I disconnected the service after mailing them, they are telling that I have got an oustanding amount of RS 401.89. I told them to deduct it from my account as I had an active ECS service. But they are cntinuously harrasing with their legal notices.