Ikea Besta drawer problem

Thanks for the tips. We will take another look at it tonight. But somehow the whole thing is screwed up...

My husband partially re-screwed the drawer rails so they would fit and cursed the cardboard parts. But even the upper doors are anything but optimal. Today I would have Ikea assemble it, then they have to deal with the hassle and possibly fix it. With our self-assembled Metod office wall, there were no unsolvable problems, only with Besta.

So I had zero problems with it. I actually can't understand why it is so problematic. Maybe the part is fundamentally assembled incorrectly, because actually everything fits.