Airtel — harassment messages

Address:

560077

For my no.[protected], message came from airtel at 8.39 am on 20.1.2019 that rs.23 deducted for validity extension for 28 days further. Surprisingly, today at 10.55 am message came from them informing that outgoing services expired and asking me to recharge.
Why does airtel wants to harass customers? First of all their new procedure of asking customers to recharge or deducting rs.23 for continuation of outgoing services is wrong form life time sim cards issued. Added to that, even after recovery of the amount, they are sending messages threatening to stop services.
I have 3 prepaid connections with them. If they continue to harass me like this, i shall port all connections to other service providers. Meanwhile i want clarification from them on the issue.
S raghavan, aggrieved customer