Airtel — unable to send or receive sms after 4g sim upgrade 3 days back

I recently got a 4g sim replacement for my mobile number [protected] and since then i am unable to send or receive sms. Also the ussd service *121# and 198 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. Now that i can't receive any messages i am unable to complete any online transactions that require otp and any other updates through sms as this is my primary number.