Somehow
really doubt that that contract will be valid, even if mc signs.
Not only will it be obvious something happened from the mere fact that simon is in that dungeon, which they can't get into any longer. But also all witness testimonies (or existence of slavery collars, if they keep them on to avoid that) will quickly clue ppl in if they didn't already realize from knowing the situation.
Feels like author wanted to force a believable evil plot into the plot, had to make it "competent" enough that it's not just a tantrum, but forgot to make it actually have any real results and not something instantly cracked down upon as soon as they exit the dungeon. Not to mention the recording, either it shows what happened, or it doesn't exist and it is obvious simon deleted it.
I hate this plot.
If MC signed, he's an idiot. Simon would never kept his BS promises. MC is just pathetic at this point.
If MC don't sign and stuggle... then some ex-machina happens... author is just out of ideas and shit hit the fan.
Best outcome based on this stupid plot is
1. MC don't sign.
2. one of the girl is heavily injured
3. MC escaped back into the demon lord room (forgot the name) and MC train or some shit to take back the girls.
In fact, I wouldn't mind if the true hero party stumbled upon the situation. But Simon party better get punished severely.
Also... how the fuck Simon and his party got inside the Abyss? Don't you need to be Rank A or S or something to enter the Abyss? Isn't that what MC fought for since chapter 1-2? Simon party got demoted and revoke the rights to challenge Abyss. This make no sense. Am I misunderstanding something?
Need to correct #2: all the girls die or stay with simon as sex slaves.
The only non ex machina solution to this plot is, like you said, that other party stumbles upon the scene (at least a couple girls would still die from being ordered to die, tho).
If mc uses his new offensive magic powers, or tries to cast status magic like usual, they'll just order the girls to die.