Impersonating isn't new on the forum. Scammers impersonate the popular user's username. For me, I don't believe anyone if send PM from any other source like Telegram before confirming via forum PM. But sadly, a few newbies don't know about such as scam attempts and eventually, they lost money. I have a similar case on Telegram where a scammer pretending me, even some of my clients lost funds. A better practice is, please add a note somewhere in your profile regarding this impersonator, so if someone visits your profile then they would notice this. At least a few users would learn from your profile.

Rather bold of this scammer to impersonate an established forum account that he doesn't have access to. We had two skype video chats and he even said he was willing to do forum escrow for the deal (his proposal), but it was really fishy that he had everything on my want list in high quantity.
https://bt.irlbtc.com/view/5330037.0

He claimed to have 7 EVGA Kingpins (5 new, 2 opened) that he bought from Best Buy (limited to EVGA's elite members only), and is limited to one per household.
https://www.evga.com/products/product.aspx?pn=24G-P5-3998-KR

Offered 22x iPollo G1-mini ASICs, yet it was limit 2 per original grin.mw forum member.

And claimed to have 2 of Innosilicon's 700+ MH/s Ethereum ASICs.

Prices weren't even that great, was asking full market value.

Had thick Russian-ish accent yet said he was from Oregon.