I do understand your frustration, RG. That makes two of us (at the very least!)
I have emailed, called to point out I had no answer and emailed again to people I was prepared to buy everything necessary for a bathroom from. I ended up buying from somebody else (probably more expensive) because I just refuse to deal with people that are unable to answer emails for business. It just doesn't make any sense to me.
My only explanation is that Portuguese are a "face" people (that should extend to "voice", too, because they (we!) are usually as polite on the phone as when dealing with people face to face. It has been noted that the normal courtesy seems to disappear in the traffic, too.
There is another thing that drives me crazy: most of those that do answer emails will not do it unless they have a positive answer to offer. That is, they are unable to acknowledge an email, to say, we will get back to you when we have an answer. Or, we can't answer you, we just don't know. I suppose this combines with the inability of saying "I don't know", like "I don't know that place, you should ask somebody else" instead of "I think you should turn right, it must be that pink building blablabla".
Sorry, I don't understand this better than you do, and I wish this could change in my lifetime!