Used stamps exchanges.

I have just received from 50stamps.club NL-054. Tried to register but comes back as "this ID for someone else" NL-054 is way too low for 50stamps.club (I received another from Netherlands and it was over 1400) Maybe this one is for another club?
It was dated 25 XI 24 and from Nieuwegein and consisted of stamps from NL and Austria + others.
No note inside. Any help appreciated.

Strange. Usually we put a note and return address on /in envelope but this one had neither.
Guess we will have to wait and see if anyone else sees this and recognizes the contents and NR-054.
(also had a Austrian cover enclosed.)

Hi! I can't find an ID from NL for you. And no member from Nieuwegein.