Error in Aarakshan

Following error was observed in Hindi movie 'Aarakshan': 

Deepak (Saif Ali Khan) is in the U.S. to do his Ph.D. from Cornell University. There, he learns that Dr. Prakash Anand (Amitabh Bachchan), Principal of the college in India where he studied and later taught, has resigned. Deepak calls Poorbi (Deepika Padukone) who is his girlfriend and Amitabh Bachchan’s daughter. When Deepika’s phone rings, the caller id on her mobile phone is displayed as +9122…….

Deepak calls from U.S. but the caller id on Poorbi’s phone shows +9122……… which is a Mumbai landline number!