Sorry to hear they haven't fixed this, and also sorry to hear that it might be hardware related.
I'm scared of doing an advanced exchange because the last time I did they sent me an even older surface, and the colours on it were quite strange but what troubles me is they've had a $1000 hold on my credit card for over 2 months, and have not removed it yet..
Not sure why you are having such troubles across the board but I didn't have the $1000 hold problem, mine was only on the card for about a week, and this was all while CARE was helping me replace my initial unacceptable exchange unit. First advanced exchanged unit was scratched, but then Surface CARE jumped in and got me a great replacement.