Phone calls bring rejected automatically on Passport

Hi. My BlackBerry Passport is rejecting calls automatically. My missed calls log is full of unanswered calls. It is specifically happening with numbers which are not in my contact list. All unknown number calls get rejected. As soon as I add the number in my contacts, calls from that number start getting through. Can anyone suggest a remedy to this.
Thanks.

Passport SQW100-1; OS 10.3.0.908

There's a solution mentioned in another thread for the same device and issue:

Attachment 325682

Source: http://forums.crackberry.com/blackbe...e-book-966196/

Also,

Though the BlackBerry 10 smartphone is able to receive phone calls and SMS messages from people that have been added as a contact in the Contacts application, when receiving phone calls and SMS messages from people that have not been added as a contact in the Contacts application, the calls and SMS messages are not received and calls are directed to voice mail instead. This occurs after restoring data from a Backup taken from a BlackBerry 10 smartphone running BlackBerry 10 OS version 10.2.1 or earlier.

Source: Phone calls from unknown numbers go directly to vo... - BlackBerry Support Community Forums and KB36391-Unable to receive calls or text messages from phone numbers not stored within a contact in the Contacts application
 Q5SQR100-2/10.3.1.1154 

Thanks a lot umaima.b.zia
Problem solved.

Passport SQW100-1; OS 10.3.0.908