Ask HN: Anyone else getting unsolicited spam from "ApplyBoost"?

I posted in the "who wants to be hired?" thread at the start of the month, and ever since about yesterday, I've been getting like 3 emails per day trying to advertise a paid prompt-as-a-service called ApplyBoost. Apparently, the only way to unsubscribe is to email back. I've done this just now, but only because they don't seem to stop on their own. Is anyone else getting this spam? Do we know who's behind it?