This has been a problem with Smart since they started . For some reason incoming caller ID only works with certain phones. I remember ringing them about it a good few times a few years ago & finally being told that incoming caller ID was only available on a Siemens or Binatone phone. This was about three years ago & I have used Siemens phones ever since. I know that they had been looking into the matter, but don’t know how much progress they have made, or what phones do or do not work now, but Siemens definitely do on my line.
Also, they should be able to tell you if CLID is activated on your line regardless of the make of your phone. On a side note, & not as big an issue some customers are finding that the first zero is missing when displaying the incoming call e.g. a call from 021123456 is displaying as 21123456. This seems to have sorted itself out on my line, but I know that others are still having this problem, but seemingly smart are working on this issue.