Test place the retainer on the cart. Orientation is important! The side that touches the bottom of the cart (negative) should point towards the top-right contact. The part that touches the side/top of the battery (positive) should angle towards the bottom left contact.

If your contacts are still too far away from the contacts, you'll need to bend them. Use some needle-nose pliers to very gently bend the contacts down. They snap easily. If they do, you can bridge the gap with a short piece of wire instead