All I wanted to know is why BA could not give out just the simple information without any details which is they are or are not yet on their way
BA couldn't give you that information because legally they were not allowed to. It's as simple as that. There's nothing hostile in anyone on this thread telling you this. I understand it's frustrating, but it is the law.
As has been suggested, next time get a note put on the booking that confirms permission to talk with you.
Captivep has summed things up very nicely in my opinion.