Airtel — unable to send or receive text messages

Address:

Prakasam, Andhra Pradesh, 523155

I got 4g sim replacement for my 2 mobile number on 15/11/2017 and since then i am unable to send or receive sms. Also the ussd service *121# gives error every time i tried using that. I tried calling their customer care however it seemed there is nobody to attend my call as i was made to listen to recorded advertisements for 5 minutes after which i hung up. I was charged 50p for that. Now that i can't receive any messages i am unable to complete any online transactions that require otp through sms as these numbers are registered.
For an alternate number i have recharged with 448 plan on 11/11/2017 with plan o[censored]nlimited calling, 1gb/day and 100sms/day but customer care has informed that today the plan gets stopped.
I have contacted nearest airtel retailer but they were telling everything is fine but the problem has not resolved