I don't think it is a refutation. Paypal did not deny they requested withdrawal permission,
they only denied that they could withdraw without permission.

Nice way of talking around the main question.

I suppose some English Grammars will call it that. That is very irritating to the rest of mankind (in the Indo-European languages).

I guess the confusion started when English lost the declinations of nouns and adjectives. Starting with the fact that "Celsius" is a proper noun, then when it is used as the qualifying part of a noun group, as in "degree Celsius", one might be tempted to call it a "proper adjective" in the sense that it is placed next to the noun that it qualifies ("degree").
That is, in the original sense of the latin word "adicio".

However, in its original grammatical function, "Celsius" is always a noun, in this case used in a noun group to qualify another noun. Calling that an "adjective" puts it (at least in the mind set of e.g. German speaking people) in a different category of word where it doesn't belong.

Let's take another example, the noun "space":

Raumgleiter = space shuttle
Raum-Zeit-Kontinuum = space time continuum
räumliches Sehen = spatial (i.e. stereoscopic) vision

Do you call "space" a proper adjective there, too?

I'm just curious ... the way we learned English Grammar at school was more aligned with the German/Latin versions but since then I've found the term "adjective" often used in strange cases in English Grammars ...