Please try resetting the lock again by following the instructions below:
Place lock in the open position.On the back of the lock, slide the reset lever into the “up” position.Insert the shackle into the lock and squeeze firmly twice to “clear” it.Pull up on the shackle to open the lock.Enter your new combination.

What are all the possible 3 digit combinations?

There are 6 = 3x2x1 ways to order 3 digits in a row. Thus the number of combinations of 3 of the 10 digits is 720/6 = 120 combinations.