My experience with A. Malaga is completely opposite.
Most of instructors I had to deal with were professional and knowledgeable.
Because of my current work I canīt plan ahead. At worst (actually this summer), I called them and asked for re-validation. They fixed my flight in 2 days notice (found plane/slot, examiner, fixed paperwork).
Never charged me a cent more then we agreed on, even when my flight lasted longer then planned.
As for Velez Malaga (airport) - I never had any flights cancelled. Not once. And in off-season they do use AGP.
Iīm sorry to hear you had bad experience with them. Well, keep in mind, they are Spaniard. Siesta, maņana.. itīs in their culture. But in my experience - one of the best school out there.
Few friends of mine did their training with Malaga - all of them had only positive to say about school as well.
Good luck with your training. Iīm sure next time you are there, you will have a lot better experience!