I have the same experience. I've personally emailed with [and gotten replies back from] both MPs[1] as well as one member of the EU Commission. I should note that it was replies from them, not their secretaries/letter-writers.

Subject was software patents and the TTIP and I spent about ~30 minutes writing an email (succinct, sound arguments, references, etc; an angry rant probably won't get a reply).

[1] Member of the European Parliament