What should I do regarding a previous fatwa that I adopted from an unreliable website, and I don't recall its details?

The preponderant opinion with us is to prohibit seeking fatwas from the unknown. Fatwa websites are considered legal entities that take the place of individuals, so one should not seek fatwas from websites whose circumstances are unknown. You should not act upon the previous fatwa, and in the future, ask reliable scholars known for their knowledge, piety, and sound methodology, or refer to trusted websites.