Something that really characterizes the dogs is their disobedience, they can become very obstinate. By calling your puppy you've probably frustrated sense, you've noticed that when you say "COME!" He will do, but ... the half hour.
They are well, well born, but you can make that change if you understand their nature.
Typically in such situations is that you end up acercándote to where he is, that's the error that you must not commit, because with that gesture your dog is learning that can dominate, and that is not what you want right? So it will be advisable to reverse the terms and teach your puppy who is in charge.