Please let me know how to deal with these situation?

[1] Delta International flight, sadly another American, put his left foot in my left arm rest from behind for a while.

[2] In domestic flight, one guy put 2 of his carry-on such that it sequence my backpack flat. I have to put the backpack up there because it's the but-head row. If I had a laptop, that will be damage. If my laptop damage, how would I deal with?