If it’s just been plonked down on it’s dropouts at some stage they might well have just closed in a fraction at the open end.
I’d maybe just have a very careful feel at gently seeing if the dropout can be persuaded to just open up a tiny before a bit before I got the files out – (mixed metaphors aside 😉 ).
Use something wide / long enough to spread the load along the whole dropout length, and just put a gentle bit of pressure on to see if it opens up a bit. Steel is quite forgiving, but I wouldn’t advocate doing this if it involves anything more than a tiny bit of easing out, as you’ll start to introduce stressors into the material beyond that.
That said if the entire length of the dropout is too tight tho’, I’d send it back, as that’ll have been from a proper knock/poor construction.
(I’m assuming this is a ‘normal’ 9mm QR/10mm bolted axle tho’).