Bro, don't get compromise your privacy for true caller. What true caller does is synchronise the contacts in which it is installed. Then it shows the name that is assigned for the number. It doesn't show a person's actual name. So if the new number is saved in the device in which the true caller is not installed, then it is not possible for true caller to tell you the name. it basically works with the principle that's called synchronisation with someone's contact .
Truecaller is a 3rd party application which is not from Samsung. we advise you to contact to the respective application software support. You can reach to the app developer through email channel for which please login to play store > select more option> select installed app> click on read more. If you have any queries regarding apps developed by Samsung, We will be happy to help you.
