Sample Buttons DDJ-SB2

I recently learned about using the sample buttons on my SB2.  They use to have 8 different sounds in them programmed to the 8 pad buttons.  Something happened where they are no longer filled with any sample.  So I added a sample to each of the 8 slots.  Now when I hit the buttons only the first four samples play. How do I get the last four samples to play from the opposite side of the deck when pressing the sample buttons?