Fogi, I think the quality differs greatly depending on the hospital and who is teaching them.
I just finished my parentcraft classes and they were absolutely FANTASTIC, honestly, I only wish we had been able to have had one or two more sessions.
I've read and researched a lot during pregnancy, and I didn't think I would learn anything new, but it was actually very informative and helpful. I felt they were time well spent.
I went to a 'couples' class with DH, and my DH went from not wanting to be anywhere near the hospital during labour to being excited about being my sole birth partner.
But I have to say that we had a particularly good midwife teaching our course. There are two midwives at our hospital who teach the class one in the evenings (my class) and one during the day- and I've met the other teacher on a ward tour, and I can't imagine that her class would have been worth the bus fare based on the way she led the tour (evasively answered simple questions ect. ect. and really annoying personality).
The structure of our classes (4 classes in total) basically covered what to expect in labour, hospital policies, what to expect in the first week home. We covered a lot about birth positions and pain relief, and interestingly- how to stand up to the doctors and midwives. ;-)
I don't know if that is helpful at all. Maybe keep trying to call (frusterating, yes) and see if you can get more info from your particular hospital?
That is too bad they gave you such short notice (we had to book four months in advance!)