Scammer impostor fake MM

Scammer's profile link: Frost
Amount scammed: $120
Discord ID + Unique Discord ID: Frost2#1339 - 794003564716228619 - He PMED me on here but discord ID is different.
Proof that it's their Discord:
Explanation of the trade: I was selling my OSRS account for $120 and someone on discord named Over 2.5 PM'd me wanting to buy it. He said he would use Frost as the MM. Frost said he received payment from Over2.5, so I sent all information to over2.5 including recovery information. Frost 2.5 told me to PM him on here and I did that, he said to send him a random code. He pasted the random code to me on discord so it's 100% his account on here that saw the code I sent to him. He then said this on discord
[Redacted]

Can someone please tell me what's happened here? Is it possible that frost has had his account compromised? The 'buyer' of the account shortly after kept telling me that he was dropping all my items and banning my account because I was a 'scammer'

 

Proof that IM came from frosts account

imgur.com

 

[Redacted]

 

They're kinda in the wrong order but you get the idea

 

Thank you to @Andy for kindly taking the time to explain to me how I was scammed. This was a fake MM scam and it was my fault not thinking about the UUID's being different. Sorry to @Frost for dragging his good and reputable name in to this mess. @Frost is totally innocent here. I just didn't think about it properly as it was only the 2nd time in 2 years I've ever sold an account on here