My new floor mats don’t fit oval floor pegs

I just bought a Monster floor mat set for my 2007 Jetta online from VWofAmerica. They come with plastic washers with 3/8” diam positioning holes, set into larger holes molded into the mats. That size hole is compatible with newer vehicles, but I believe all MK5 Jettas have oval posts in floor, with a top section that rotates 90° to hold mats down in place, which need a larger oval hole in the mat to pass through. The plastic inserts in these new ones feel like they may be removable, to allow a different MK5 insert to be used instead. Does anyone know how to make the switch?

I complained to VWofA, because they originally indicated these mats were specifically matched to my VIN, which I supplied them. Their only reply was that I could buy “a set of securing attachments” along with a part number that doesn’t exist. Help?