I would hereby like to share my personal experience with mobile service provider Airtel, perhaps a bad experience. I have had a corporate connection since years which I have been using. I had opted for an internet plan for Rs99 which provided me benefit of unlimited 2G internet. Suddenly, the company stopped this plan and they billed me so heavily that my bill shot up from 200 to 2000.
This was totally insane and it all happened because the company discontinued the plan and further without informing the customer they changed the plan to a limited one. We as a customer would use it thinking it to be the same old unlimited plan but it was a limited one. Ideally, we get promotional calls but for such kind of information there was no call no intimation. Really disappointed!