My dad uses Airtel postpaid and his monthly bill shoots to 550 to 700 occasionally. I tried mypack option it doesn't work well. So thought of switching him to Vodafone for better plans. He doesn't use 2g or 3g, max if he uses it will be 300 Mb per month, all he need is a good call (local and std pack) Is it wise to shift operator for this alone?