Airtel — Airtel stopped SMS sending in Rs.49 pack

Hey, I'm using an airtel SIM whose number I have given everywhere in my official documents.
I don't use the number much except receiving OTPs and sending my Bank SMS.

I do recharge of ₹49 every month, which gives me talktime of ₹38, but I am not able to send SMS.
On calling airtel they told me, that they don't provide SMS sending service in lower packs. They only provide SMS sending service in Unlimited packs

Please look into this, if I'm having main account balance of ₹38, why can't I use it to send SMS