On the top of the rectangle part of the negative contacts, there is a tiny latch, be sure to place this on top of the USB port when replacing your contacts.

Gently place the negative contacts on top of the USB port.

The negative contacts are going to over-extend their correct slots, once you have the latch aligned on top of the USB port, carefully push in the sides of the contacts and lay them into their correct slots.

DO NOT force the negative contacts down. This could break the plastic or the metal.