Guys, the tables have turned!
Suddenly Vodafone has impressed me after the initial bad impression. After every call i make to the customer care, i get a feedback message wherein i am supposed to write whether i liked the service or i was disappointed. i, but of course, wrote the latter. (the reason is mentioned in the first post.) 2 days later, i got a call from a Vodafone executive asking me the reason and i explained everything to him. he noted it down.
Now, three days back, another Vodafone exceutive called me to discuss about this issue that i had mentioned in the first post. he enquired whether the net connection is active right now to which i said yes. he also apologized for the error & said that the Rs. 40 deducted from me would be credited to my account! That is really impressive on their part.
of course, he did mention that if i am happy this time, i should write "yes" in their feedback message this time, which i would again be getting (which i did). So, this feedback thingy of Vodafone really works!