Default Need some advice

I bought an HTC ONE from swappa. The seller has sold one other item, an iphone 5s. He listed it in great condition but that was it. It was 260 bucks, I had good experience with Swappa so I bought it. When it arrived it was not stock, the boot loader was unlocked and it was running Revolution HD, would not connect to google services and was spotty on the data connection working.

I messaged the seller and he claimed not to know anything about rooting, or putting on a different rom etc, so I asked him if he was the original owner. He replied no he bought it about two weeks ago (I had bought it on 3/22). So as I was digging on the phone to try and figure out what was going on I saw files in the sd card in download - from 3/5 3/15/319.3/21 and so on. He also had pictures dated up to the 21st, and I found the zip for revolution dated the 15th.

I aslo found a downloaded doc for a insurance claim on cell phones..which set off a red flag. I contacted Swappa and told them these things and they thought it was concerning that he seemed not to know anything about flashing etc.

He replied in my sales thread to swappa that he could not believe they would just take my word for it that how do they know I am not lying about it..

SO..in the same sales thread i posted screenshots as proof, since he left screenshots of the phone on it..

http://imgur.com/NWO5yZ6

http://imgur.com/4LfQO5y

http://imgur.com/6CPau3C

You can see then above...and he still insists he knows nothing about it and then went off about me and the staff siding with me and I ruined his first sales experience and on an on but still insisting he knows nothing about rooting and images and roms

at this point I don't know...I am afraid he is going to file some sort of lost or stolen phone claim and screw me. His insisting he knows nothing about roms etc even though there are files on the phone up to the day before he shipped it to me..or do I just accept he got caught in a lie and keep the phone...

any opinions?