[Sentinel]

Unless your phone got cloned. So unless you passed your phone to anyone and it was away from sight. But if your phone got cloned, they will not even have to call you cos they would be impersonating you with that cloned device...

Ok, no way to clone the phone (with your number)

If you want the number on more than one phone, the Telco has a service for you to subscribe to, for example M1 has that service