Airtel — I have done lifetime validity plans

How dare airtel stop incoming calls for a prepaid number when there is validity till 2037. Airtel is harassing it's customers to get a minimum recharge to get back incoming services. Where on earth is there a rule that u can block incoming calls for a prepaid number which is active.
I will definitely lodge a complaint in the consumer court. I will sue this bloody company. Exploiting customers has become a game for you companies. Your network horrible. Never could i use the data due to very poor connectivity.