I have done all that. I have read all the posts... I just didn't feel like typing out every single detail.
What is your latest "message" in the phone app? Does it tell you to "Expand your view" by spying through the vent? That would make the MC realize they can see more because one of the boxes is gone, so he'll ask the store clerk to buy the rest of the stuff. Try talking to her after picking up the trash to see if you can buy all the signs now.
If your phone doesn't have the message then it COULD be that you shouldn't have messed with the sensitivity (completely unnecessary to cheat it, imo, since you will build it up quickly just by watching the H-scenes twice a day), however I'm not sure the trigger is actually linked to reaching a certain sensitivity. It is possible though, since originally one of the areas only unlocked if you got 4k money the "legit way".
For future reference, "not feeling like typing what you did" is actually very counter-productive when you're requesting help. Breaking down what you did, what your current state is, what the game tells you, etc. will help others skip past those things and suggest things you haven't tried yet.