We reserved the Grand Family Apartment two months in advance, paid a deposit, and received an explicit confirmation of our booking. Then, at 5pm the night before our arrival, I received an email stating that "due to an error" the apartment was no longer available but that we could stay in the "Cave" apartment instead - darker, smaller, and on the ground floor, which was hardly what we had in mind. After two hours searching online, I luckily found another place for us to stay.
Whatever the reason for the last second cancellation of our reservation - innocent (which seems unlikely) or otherwise - it was incredibly frustrating to have our plans upended at the very last moment, requiring that I spend two stressful hours searching online for alternative accommodations when I would have much preferred enjoying our last evening in Athens. Completely unprofessional and disappointing. Consider yourself forewarned.