Airtel — prepaid sim "not dialing a valid number"

We purchased two prepaid sim cards at the airtel shop at mumbai airport. We are not able to do any phone calls.

- the provider is set to airtel only
- the phone is connected to airtel
- ussd codes are working
- all numbers dialed result in a speech message saying "you are not dialing a valid number"
- the same when dialing 59059

We haven't been informed at the shop (Despite asking) about any special procedure required to get the cards working.
There is none mentioned in the package of the card.
I am wondering if a verification step (E. G. Via 59059) is needed after all (A copy of my passport and a photo have already been taken at the airtel shop).

The airtel support is a nightmare. Via email and via the website they ask for an authentification before answering any questions. The authentification involves sending a password by sms - this, of course, does not work without the mobile connection...

Another airtel shop in pune gave us the hint to call 59059 which is not working also.

In my opinion the only thing to do by airtel is to enable the cards on their side. It's a piece of impudence to block every bit of support.

Prepaid phone numbers:
[protected]
[protected]

Arnold