Incoming mobile numbers not displayed

[grahamm7]

My wife has just purchased an LG K4 Smart phone and is with O2 on pay as you go.  All her mobile numbers on the old SIM card (pay as you Go with O2) that was in her old Dumb Samsung phone have been transferred on the SIM Card to the new SMART phone.  However when any one rings her (who is in her mobile LIST on the SIM card) the number is not displayed on the phone.  It just says Private Number !!!  I have searched all the settings to see if something needs setting can't find anything relevent.  I then transferred a VCF card for me (husband - techie fix it guy!) to her phone.  This works on my LG K4 with Virgin Mobile.  The contact list displays all this information ok. If I ring her new LG 02 phone it still shows me (against the new VCF transferred info) as private number.  Any ideas out there. 

[MI5]

Go into contacts and then settings and transfer sim contacts to phone.
This should enable the caller ID.

[Anonymous]

Perhaps they have caller ID set to off???