This recalls my experience in the US where I had been staying in my daughter's house for 6 months. I was not using my airtel mobile connection throughout my stay there and all my incoming calls were expressly asked to be made to my daughter's numbers. Of course, I was using whatsapp. Frequently my mobile was ringing in the dead of night. The calls were from the same number. In spite of daughter's warning out of curiosity I received the call once when it came in my waking hours. Some Hindi talk I heard and I immediately cut off. Daughter said after doing some investigating they were some fake calls from Mumbai . I too was charged for that nuisance call. But I learnt my lesson!