Does the non-answering of supplication despite persistence indicate a defect in one's creed?

Question:
May Allah reward you and bless you. Honorable Shaykh, this person asks, and in his question regarding supplication, he says: If a person supplicates for the removal of a hardship or the relief of a distress, and this matter continues for several days and several months without being answered, is there a defect in his creed?

Answer:
One should not despair or lose hope of being answered, for the Prophet (peace and blessings be upon him) said . It was asked: How does one hasten, O Messenger of Allah? He said: He says, "I supplicated and supplicated, but I was not answered." And when a Muslim supplicates with a supplication, it is not lost with Allah; either he is hastened an answer, or something better is stored for him, or it is delayed because Allah knows that it is better for him in his future. So he entrusts the matter to Allah. Supplication is worship, indeed it is the greatest of the types of worship. Yes.