I was given this link to request missing albums, although it is in French:
https://airtable.com/shrb4MODKBO0DGaNQ?prefill_SourceFR=Utilisateur
I can’t vouch for how effective it is, I have requested so me albums that did appear some time later (although they might have anyway) and some that still haven’t been added. I didn’t receive any comms in response to my requests.
Good luck