Have problems next to my current htc touch diamond ?

Ok so I got my htc touch diamond. [excited]
Whenever someone calls me[example my best friend,boyfriend,friends] it other says "unknown caller" even tho i put them into my contact list. is at hand any way i could fix that?

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Answers:    Do you have christen display included in your plan?

If you do and it's not showing call your carter to add it.

Or your friends could have witheld on; making their number private

Or... if it only just shows the number then it's the phones problem.