@MartagonLilies
I think it's be fine for them to give you the code. I agree with pp who mentioned that you should have an exit not involving any codes.
Also, and I know this is totally not relevant to your aibu I just have to ask, do you really have PTSD?
It's a serious thing, resulting from a seriously traumatic experience in someones life, such as cancer, sexual assault, military combat, abuse among other distressing, life altering situations.
The results of suffering from PTSD take over peoples day to day life, to the point that they are totally controlled by it.
If you do have this, you should really seek treatment. If you don't, and just have some unpleasant memories, than you should stop claiming you do have it.
How rude! 
You can have PTSD from ANYthing that has hurt or upset you, or freaked you out.
I was locked in a dark, built-in wardrobe, by my cunt of a male cousin when I was 7-8 years old, and left there for THREE HOURS, while he fucked off out. (My parents just thought I was playing out with my cousins...)
It was 30 years ago, but since then, I have suffered crippling claustrophobia, and freak OUT if I am in a small space (or even a small room) where I cannot get out. I literally cannot get into a lift, and frequently have to walk up 4 to 8 sets of stairs at work, and when I go anywhere that has a number of floors!
I also cannot use a portaloo on the street or a train loo as they shut electronically, and I basically cannot go into anywhere with a door that locks, if there is no other way out! Some days, it has a profound affect on my life, and is a pain in the arse.
Who the hell do you think you are to accuse someone of making shit up like this, or saying people only have PTSD after being at WAR, or a serious assault etc?
OP, YANBU, and you DO need to get this code. Can you not go back to the person you bought the place from?