The very fact that turning the "D" handle does not cause the windows to go down points rather sharply at the PTCM (power top control module).
The windows going down is fundamental. I"m actually having a hard time understanding how they could screw it up this badly. A blinking light on the top switch (is that the one you refer to?) indicates that the PTCM is alive but confused or it sees sensor inputs that make no sense to it. But it also means that the "brain power feed" is OK (so that fuse is OK). I'll think this over a bit and tell you what I think when I come to a guess as to what is going on.

Did it work when you got the car back and then fail later, or did they return to car to you not workintg?