It's a shame that this part of the holiday is being spoiled and I am sorry you have all been ill.
Surely the first thing to do is to contact the owner who may believe that the maintenance company he will almost certainly be employing is doing whatever is necessary to keep the pool clean, as they are paid to do.
It won't take much to put the pool right with the right administration of chemicals and he should be given the chance to kick butt and make sure it is put right, if it hasn't already been sorted out, which I hope it has and that you are all ok.