What is the ruling on their saying that someone saw the future?

The meaning of "seeing the future" might be contemplation and reflection on the consequences of matters, which suggests that purchasing a specific commodity is more beneficial. As for claiming knowledge of the unseen, it is a lie and a delusion, because knowledge of the unseen is exclusive to Allah alone, as He says: "Say, 'None in the heavens and earth knows the unseen except Allah'" [An-Naml: 65]. In the context of commercial marketing, the term "seeing the future" may refer to foresight studies of consumer behavior to achieve desired results, and there is no objection to this usage because it does not claim knowledge of the unseen.