I'm sorry to hear you had this issue, but why would you use two sets of floormats? The hook that comes on the floor of the ****pits is only high enough to hold one set of floormats down, so it doesn't suprise me that a second layer of floormats would move around freely.
Try using the aftermarket mats to REPLACE your OEM mats instead of LAY ON TOP OF them. That should fix your problem.
