Vodafone India — billing

On the last night of my billing cycle i still had 500mb data out of 5gb quota. After midnight i continued with internet usage (Since quota was going to refresh). And suddenly after 35 minutes one alert message popped up, 19.95mb data usage as per standard rates. I called customer care but they didn't give satisfactory response and hence i changed the plan. Vodafone did not give me alert message about cancelling the free internet quota. Just informed me after usage. After bill generation i again called customer care but they are not accepting their fault and lying that they informed me before 10 days. Now i want that rs. 119.56 charged for 20mb should be cancelled. But company is not responding positively.

-ajay