He warns on his post about an impostor Naober called @Haober on telegram...
His customers are well aware about the imposter in telegram but the real Naober (@naober) recently has also went on a scamming spree. There are already 3 cases and yours makes it 4 (provided backed up by proof which you haven't yet). Check his trust profile.
At this point it is safe to not to deal with naober for the moment until the scam accusations are addressed and resolved by him.
He used to be good at dealing.
He's suddenly starting to cheat...
That's another way how scammers roll- first do some trades to gain trust and once he had done enough and have gained community confidence as a trusted trader ,they will go on turning into a scammer.
He is not the only one, there were lot others and people had lost so many earlier. There are lot of old stories but there is one conclusion that users here needs to learn- trusted or not, always use escrow.