Nobody tell banks about fortnights
alkheemist
"Trust me."
Near the bolt holes joining the two halves, you can see thin strips going across that overhang gap. Those eliminate local sagging without needing support material. The part could have been flipped 180 instead, but then the outer edge rim would be unsupported.
Those deep holes in plastic parts are always the worst. If you have a dremel you have 2 options. Either cut away enough of the top plastic that you can get at the screw to dremel a slot into the top, and unscrew it with a flathead screwdriver. Alternatively you could try dremel just below the head of the screw to cut the screw in half.
if you have a soldering iron you could also try heating the screw to melt the boss it's screwed into. You might have to cut/melt away plastic to access the screw and then apply light rension while heating so that it opens once the screw is hot enough.
If you really don't want to spend money, there's always GNU Octave. Sure, it doesn't have the thousands of matlab toolboxes, but if you're running code from 40 years ago it shouldn't need those anyway. I wrote a couple of scripts recently and then rewrote them slightly so that they would be compatible with octave.
Lossless Cut FOSS, Crossplatform frontend for ffmpeg. Note that to do it losslessly, it will still be in mp3. If you need to transcode you can do that too, but like others have said you'll probably lose quality.