Just my experience about "nadjib d"
I had bought ARC AI from "nadjib d" for $250 (negotiated price, original price $360). After few weeks, he released new version, so i requested an update from him. He denied update saying i didn't pay full price originally and if i need update, i need to pay $140 more. If he had told me while buying, i wouldn't have bought from him. Just to be aware.