Airtel — airtel gave me life time validity

Airtel customer care told me that your outgoing service will be stop on 24 Nov 2019 so you need to recharge minimum 35 for validity only and if you do not recharge then your Incoming service will also stop after 15 days. He also told me that you have to recharge after 28 days for validity if you done the recharge with 35 Rs. I asked to him that i will have to recharge time to time only for the validity, He replied Yes you have to recharge time to time for the validity only. But when i purchased the Airtel Sim Card that time Airtel gave me life time validity. Now Airtel is cheating to customers.