Complement IKEA drawer assembled incorrectly

Hello, I have a problem with a Komplement drawer that I assembled incorrectly. I inserted this plastic screw thing upside down (with the closed side facing outward) into the hole. Now the rail can't click into place. But I also can't get the thing out anymore, is there a trick for that or do I have to go to Ikea again?

Do you mean part 102349? Then I would just drill through it.

I made the same mistake and used a corkscrew to get the thing out again and plugged it in the right way.