So the following is not regarding a Torah insight from something like an angel. But if a person receives a Torah insight through siyata dishmaya, namely G-d plants a Torah idea in his head he shouldn't ignore it.
The Sefer Chasidim 530 writes:
וכל מי שגלה לו הקב"ה דבר ואינו כותבה ויכול לכתוב הרי גוזל מי שגלה לו כי לא גלו לו אלא לכתוב דכתיב (תהלים כה יד) סוד ה' ליראיו ובריתו להודיעם וכתיב (משלי ה טז) יפוצו מעינותיך חוצה וזהו שכתוב (קהלת יב יד) יביא במשפט על כל נעלם שגורם שנעלם אם טוב שגילה לו אם רע שאינו כתבה.
Anyone to whom Hashem has revealed something and he does not write it down, though he had the opportunity to do so, is thereby stealing from He Who revealed it to him - for He only revealed it to him for the purpose of recording it, as it is written, "Hashem reveals His secrets to those who revere Him; and His covenant does He make known to them" (Tehillim 25:14), and it is written, "May your wellsprings burst forth" (Mishlei 5:16). This is the meaning of the verse (Koheles 12:14), "He will bring [man] to judgement over every hidden thing, good and bad" - Hashem will judge the man who keeps hidden the 'good' that He revealed to him, and did 'bad' in not recording it.
So it would seem from the Sefer Chassidim that if one gains heavenly assistance in the area of Torah it is incumbent on that person to not just ignore it but rather to take active steps to record what has been given over to him.