Cellphones, in general, do not work properly with caller id.
They either display:
1. The name that you have the number saved under in your phone, if you have the number saved
2. A name that Apple 'Proactive' Intelligence has pulled from email data on your phone
3. If no information is available sometimes it will display the town associated with the number
Below is a more detailed explanation of Apple 'Proactive' intelligence feature, and caller id behavior.
How Caller ID and the CNAM Database Works:
1) Caller ID name is controlled at the telephone number level, not at the extension level. For every telephone number on our platform, we enter a CNAM listing into the national CNAM database. All other national carriers (AT&T, Verizon, Sprint, etc) use this database to update their own records for Caller ID. This is how for example, when a telephone number is reassigned from one individual or business to another the correct name is updated.
2) Caller ID is comprised of two "lines". The first line of caller ID is your telephone number and the second line of caller ID is the CNAM (Caller Name). Most all landline services will provide both lines of caller ID information (both number and name). Most all cell phone providers only provide the first "line" of caller ID (phone number) and they provide a general calling area for the second line.
How Apple iOS 'Proactive' Intelligence Works:
What you are experiencing is not a result of an incorrect listing in the CNAM database, but a result of Apple iOS 'Proactive' intelligence feature. While 'Proactive' intelligence encompasses a large feature set, the three features that we are concerned with are:
1) If a call comes in from an unknown number that is contained within an email you have received, 'Proactive' lets you know who might be calling.
2) If a call comes from an unknown landline number that isn’t included in any email, 'Proactive' will tell you where that number originates.
3) In line with 'Proactive’s' strong focus on privacy, contact suggestions come from on-device data, not server logs. And because they’re enabled on a per-device basis, suggested contacts might differ from one device to another.