Crumbs of white material (looks like little bits of foam rubber) under front seats, then the stitching failed

[GeoMetry]

My car has 2.5 years old, I have about 30K miles on it. I am 6' tall and 160 pounds. I don't carry anything in my back pockets. One of the stitches on the drivers seat started coming out after about a year and a half. I took it to Tesla they replaced the seat cover and charged me a bit more than $500. They said it was not a manufacturing defect and not covered by a warrantee so I asked to have the old part and they gave it to me. Now that I look at the old part I think the stitching problem was caused by something rubbing on the inside of the seat perhaps when the seat was moved forward and back because the lines where the rubbing occurred appear to be in those directions. I never thought much about it before but every time I would clean the inside of the car there were white crumbs that looked like bits of foam rubber under the drivers seat. I believe I can see the source of those crumbs now, it was a piece of material attached to the original seat cover. I think that the rubbing is also the cause of the damage to the stitching. Has anyone else seen this problem? Did anyone get this fixed under warrantee? The green pen in the pictures is just there to help you see the relationship of the rubbing marks on the inside to the loose stitching on the outside