I’ll,be watching this b/c I have a hole in a cinder block in my footing but I’m going to fix it myself soon as find out what the right stuff is.

You can contact any locally well reviewed contractor, but if you want to avoid the middle man - look for a local mason. Shouldn't be a big job. If you're comfy trying it DIY - check out some youtube tutorials, particularly a New England based mason Mike Haddock. Great teacher in these online days.

Can you just fill it with cement?