Yes, you should DEFINITELY demand that the roofer return immediately and fix his incompetent screw-up AT NO COST TO YOU.
I don't know where he got the nerve to call himself a "roofer" - I don't wanna start name-calling openly, but the name I would prefer to call him rhymes with "plucking ash sole", if you catch my drift. Blocking a vent like that is dangerous, illegal, against code, and just plain damn stupid. The sewer gasses are prevented from escaping, and - more importantly - the lack of venting can result in a siphon condition inside the pipes, which will suck the water out of the fixture traps, allowing sewer gas a free first-class ticket into your home.
Call that so-called "roofer" back to fix it up (at his OWN expense) ASAP - if you forget about it and let it slide for too long, you'll only make it easier for him to tapdance out of his responsibility. Get 'em while it's hot!
Let us know what happens, please.
Moishe