If your battery does not latch into place properly, we recommend pushing downward on the battery itself after you swing the battery in from the side.
You will also find a black cover near the top of the battery on the bike frame itself. If you remove this cover, there are screws that hold the lock cylinder in place. You can adjust the lock cylinder as needed using this hardware, and test removing and reinstalling the battery before the black cover is put back into place.
If you are still having trouble, please contact us to open a service ticket, and we can provide additional instructions as needed.