There are several posts here on this board already concerning this issue.
If your phone says just call or incoming call it's probably because your service provider has not enabled caller id. So you have to do what I suggested above.
If you on some late point will experience your phone showing just the number of the caller even though you've already have it as an contact, it's because you have duplicated entries. - Like you have one number saved as two or more different entries (e.g. Dad, father, John) Then the phone gets confused and that resaults in showing no names and just the number.
But if I understand you correct, you will have to call your operator and explain the issue.
Cheers!