Unknown Caller ID for Contacts.

[James_A]

All my Incoming calls are Unknown, which includes Contacts stored on phone. 

I have caller ID and Spam protection turned on. 
I have reset Phone on numerous occasions, problem still remains.
This problem arose when I changed my Sim card to a new one. Believing the new sim to be faulty I got a new one, to encounter the same Issue.
My number has not changed since I first contracted with O2.

Any suggestions on how to resolve this matter would be appreciated. 

[pgn]

Take your phone and photo id to an O2 store, a replacement SIM has fixed this recently for another customer here. Good luck, don't let the cowboys in store sell you anything either, @James_A 

[James_A]

Thank You for responding PGN, 
My previous sim encountered this problem. This is the second sim card that has encountered the same issue. 
Why would 2 brand new sim cards encounter the same Unknown caller ID issue for all Incoming calls?

[MI5]

@James_A 

Try turning off wifi and 4g calling in phone settings to see if it helps?

[James_A]

Thank You for the suggestion MI5,
Turned off 4G calling (wi-fi calling was already off), reset phone and still same issue. 

[MI5]

@James_A 

I'll ask @O2Sarah- to check in with you in the morning.

May need CLID resetting on your account.

[James_A]

Many Thanks MI5.

[O2Sarah- · Accepted solution]

Thanks for the tag @MI5 

@James_A I will send you a private message so we can check your account. 

[Woody45]

Hi having same issue on sony Experia since getting new O2 simcard after switching from virgin ,tried everything  .

[Bartosz-88]

Hi , I got the same issue . All calls come as unknown and it’s affecting my business . Need to get this sorted asap . Please someone help me