I spoke with Dardenfall and he told me that he had given the games he offered to 113Allie but never received anything from her.
She never responded back and went silent. Later on Dardenfall found out that his keys were used.
I added 113Allie on Steam, in order to talk with her( unfortunately could not post on her profile because the comment section was private for non-friends ), but my request was declined.
Couple of days after that I was added by 113Allie after she saw this thread on the forums - http://steamcommunity.com/groups/bartervg/discussions/0/353915309335355778/
She indeed comfirmed that Platypus (http://steamcommunity.com/profiles/76561198120636624/) is her main and that 113Allie is one of her alt accounts.
She said that about a year ago her alt 113Allie was hacked, stating that she didn't know about the dispute, implying that it probably was the hacker, that made the trade with Dardenfall and stole his games.
I asked Platypus ( with alt 113Allie, that is now connected to her main on Barter ) if she would reimburse Dardenfall ( and the other two victims from other disputes ), to which she eventually agreed. She offered to reimburse each victim with 1 CS:GO Key.
I managed to trade with her for those keys and provide Dardenfall his reimbursement.
However I would like to mention two things from my research:
1. I asked Platypus to provide screenshots of her license and product key activations, so that I can compare activation dates of games from her library( that match games with the same titles below ) and the date this offer was accepted. A Fistful of Gun and Batman™: Arkham Origins were activated on 26 of July 2016 on Platypus' account. The Cat Lady was not found neither on Platypus' account, neither on any of her alts.
2. When I asked Platypus if 113Allie was the only account of hers, that was hacked she said that, as far as she knows it is the only account that was hacked and no other account of hers were hacked, at least not to her knowledge.
However I went to check the groups of the supposed hacked account ( 113Allie ) and I did not found Barter among the groups. So I am not sure why someone would want to hack the account 113Allie (since the account itself is not worth anything, form what I can see and back then it probably had even less games).
Also why someone would not only hack it but decide to go on a site, called Barter.vg and steal some bundle games? - the scammer could not know that 113Allie has an account, specifically on this site, especially when Barter is not part of the account's groups, or indicated anywhere on 113Allie's profile.
That is everything I have found from my research. 18 months ago