Airtel — new 4g sim not working

Swapped a 2g sim for 4g yesterday evening and received a message that the new sim has been activated. However we are unable to make/receive calls. Caller is said that the number is out of service. Further on calling from the number, nothing happens and a message appears mobile network not available. We are not even able to use basic ussd codes. To aggravate the matter the insensitive customer care guys said that everything is fine from their end. Though after calling even they realised that the number was unreachable. Instead of resolving the issue, the support aggravated the issue by mentioning that there has been sufficient data consumption on this number though there has been none from our end since this number is only used for calls and was even the data meter in the mobile set shows 0 bytes of data consumed. Till yesterday, it was in an old moto l6 handset and since yesterday it is in moto c plus in which we have specifically switched off mobile data since we have wifi at home. We are not receiving basic services (Like call/ussd codes etc let alone data services). Take action urgently since it is become really troublesome without call services. We have checked it in a different handset as well and it is not working whereas a vodafone sim is working on both handsets