I had a Airtel 2G sim which I upgraded to Airtel 4G sim because I was getting the message that you have a 4G handset, Visit the nearest airtel outlet to uprgade to Airtel 4G LTE and get 2 GB 4g data free by just dailing 52122.So, I upgraded my sim and thought that the data and call rate will be not high.But, I was wrong , After upgrading to 4G , I got 2GB 4g data but the data is over in only one day.So, I thought that I am going to recharge the 4g data pack but the data recharge and call recharge are very much higher than any ohter service provider.Also upgrading into 4G sim , sometimes the network bar totally disappears and I am hugely disappointed by this type of pathetic service from airtel.I also tried to reach the airtle customer care by dailing 198 and also from my airtel app but The network problem did not solved.