The first question is did you use the proper driver and it was not worn out. As that can be the start of knowing if the issues is not having the correct purchase to twist the screw out. Yes, it's likely a bit late for that, but trying fresh screwdriver might work.
You might want to try a little bit of solvent or penetrating oil like WD40 which can seep into the threads to hopefully loosen the bite of the screw. Next if there is enough of a head is to use a jewelers pin vise that can grab the outer wall of the screw, a serrated plier could also work. Using a bit of heat and cold a few times can also break the seize.
The last and one you need to be very careful is drilling the screw out. Here I would use a left wound drill so as the bit bites it helps remove the screw body. Use a drill which is smaller than the I.D. of the screws shaft.
You need to hit the screw smack in the middle and not drift. Make sure the metal shavings don't get into the system.
crwdns2934105:0crwdne2934105:0
crwdns2934113:0crwdne2934113:0
crwdns2915270:0crwdne2915270:0
crwdns2889612:0crwdne2889612:0
0