If you want them to go north and they insist on going south, don’t force them to turn around. That’s an obvious and metagaming method that players catch onto easily. An old trope that spoils the game. Instead, either move the goal (you are the DM, right?) or add a step that lies in the South (or whatever direction they decide to go) that will gently bring them back to where they need to be. And, if you’re subtle enough, they won’t even catch on.
Other ways to divert the party
1. Move the goal
2. Add side goals on the fly…oops, is that a cave?
3. Draw attention to the real goal…NPC dies or is murdered.
4. Dead ends…murder, kidnap, someone else snags the prize.