Looks like you need to turn on the "Keep Faces Together" option. To turn it on after an extrude has already been done, you can find it in the Channel Box when you select the particular Extrude history item.

To have it on to begin with, you can turn it on under Polygons > Polygon Tool Options > Keep Faces Together.

Also, watch out for the extra faces you have... you can see them as a face component handle on an edge. I can see a couple in the screen shot.