My sympathy. While I'm fluent in French I don't know bike vocabulary beyond the basics like guidon, roue, pneu, crevaison, and I'd also have difficulty explaining that the wheel was buckled over the phone.
Just a thought, because it seems pretty unusual to get a buckled wheel fresh from the start: are you sure that it's buckled and not just fouling the stays because it's not sitting properly in place? Taking it out and putting it back in might help get it to sit correctly.
(Putting in an old wheel with fewer gears on the cassette is not going to be a good fix either - the bike's gears will be indexed so that they are aligned with the new wheel's cassette.)