Did you check whether the seller had any recent successful transactions or feedback
Yeah, this is the first degree to get an actual point of view, esp. these days where scammers try hard to... ..well, scam people.
-- -ADR-
The irony: the user "thomasfrank" you responded to was a forum spammer himself. Account deleted.
I have suspended the suspected scam account @malexito.
Beep, Bopp, Bleep: info@modulargrid.net