Can't obtain new grimoire to take part in meebles

Platform: Windows
ISP: Andrew and Arnolds
Type of Internet Connection: Fibre
Internet Connection Speed: 80MB
Date & Time: 30th November 2014 20:42pm GMT
Frequency: Always
Character Name: Yoleh
Race: Mithra
World: Phoenix
Main Job: Thief 99
Support Job: Dancer
Area and Coordinates: Sauromugue Champaign (J-7)
Party or Solo: Party
NPC Name: Burrow Researcher & Burrow Investigator
Monster Name:
Steps:
Missing a Diligent Grimoire, possibly by disposing of it by accident.
Talked to both Burrow Researcher and Burrow Investigator in Upper Jeuno.
Selected option Purchase a grimoire.
Response from both NPCs was: Our coffers are empty. We don't have anything available for purchase.
No option to retrieve a grimoire in case I had already traded it to them (same results also in Batallia Downs.)
Not currently in possession of the KIs to indicate that a grimoire had already been exchanged for them.
Party leader couldn't enter a burrow investigation with me in the party.
Talking to the NPCs to enter refused me entry into the burrows.
GM response was unable to help and informed me also that the Diligent Grimoire was unrestorable and suggested I make a bug report.

Somehow and I don't know how but a grimoire just appeared in my inventory. I might've been given it when I spoke to the NPC the first time and just hadn't noticed. I'm sure I didn't get a notification about it and the conversation has already scrolled off the screen so I can't recheck if it was just a case of me not noticing. I'm totally baffled.