I bought OEM Chrysler slush mats for my car last fall and had the same problem. If you look at the under side of the clips on the carpet mats, it has a Mercedes emblem and part number. The slush mats do not and the clip itself is different. I went to a Mercedes dealership and bought two sets of clips for an '04 SLK and replaced the ones on the slush mats. They now stay in place like they should. If you need the exact part number for the clips I bought, let me know.