Defeat the Time Patrollers
Once you accept the challenge, it’s time to fight. You will be up against three combatants at once, each of a different level. These levels are completely random but you’ll almost always end up with at least one opponent who is higher than level 30, which is why you were suggested to be level 35.
You’ll have to defeat all three, but when you defeat each individual one, make sure to pay attention to the bottom of your screen. What you’re looking for is the reward pop-up (it’s a black bar with white lettering). It will say what you’ve earned from each victory. You’re going to want one of them to say Key Item, that means one of the opponents dropped one of the Dragon Balls. If you see this pop up, continue the quest until completion.
If you don’t see Key Item, restart the quest by pausing and choosing Retry.