Well, this hasn't happened to me, but I think I would certainly make a big stink (politely, at first) about it. I can remember a suitcase of one of my students was misplaced for three days (VERY inconvenient to a teenager traveling) When the suitcase was returned there was a $100 in the suitcase as compensation. That was in 1991. So I think in view of the ENTIRE VACATION PLUS, I think you should be seriously investigating your rights regarding compensation.
I am a little puzzled about your "colleagues' luggage" during YOUR vacation, but maybe you are just addressing a additional luggage problems with Iberia.
In addressing your vacation luggage, I would stick to that problem since that seems concerning enough. I know the max. liability per piece of luggage is not that much, but I don't know what it is. You might address that with Iberia since you don't have a bag. Period.
Iberia has a Miami office to deal with ASAP.. I would ask information for 800 # for Iberia offices, not reservations.