I haven't thought about contacting them before. Although I think that's what my broker should have done (as it seems to be a 'server side' problem) I've just reported it to them now. Let's wait for their answer.
Just saw you thread today, 1 year later.
I'm from Brazil too and use both XP and Clear accounts. I'm able to get the ticks either from MT5 terminals or through code that I developed using CopyTicks().
I suppose the problem is that you are trying to export ticks from a symbol used to compute what MT5 calls "continuous series", meaning that they assemble information from various contracts into that symbol so that you can plot a continuous chart using that symbol. They perform some calculations on the data to adjust the values based on different methods, this is why you have WIN$, WIN$D and others.
You have to use a real contract name to get the symbols, like the current WINJ18 for example.