Vodafone India — sim deactivation

I haven't been using my number for 3 months. I haven't been paying the bills either. I had gotten smss warning me of the services being interrupted/becoming inactive but i'm still being billed every month instead of deactivating the services. The first time i called the customer care, they've asked me to pay the month's bill and they'd deactivate the number. I paid the bill even though i hadn't used the number and called them back. Then they asked me to go to a vodafone store. I really don't want to waste my time going to a store on such a trivial matter. Why can't vodafone just stop the services and stop billing me? I have set a credit limit of 800 but somehow my present withstanding bill is nearly rs.1, 200. Please deactivate my number or stop the services and stop billing me.