Hi sekhmut
That's disappointing news.
Yours were C. aeneus, weren't they? If so, you have a good chance of them spawning again soon. Why not set up a small breeding tank and move the corys into it? Then, after they spawn, you can move them back, clean out the gravel, etc. and let the eggs hatch right there.
I always lose a lot of them whenever I have to move them. They are delicate and it's so very easy to damage them just by touching them.