It annoys the heck out of me too. Generally what I do is reply with the remaining questions they haven’t answered; sometimes they get the message and answer all of them, sometimes we go round and round until I have all the answers I need.

I work in IT so for the most part, if I have 5 questions, that’s because there are 5 things I need to know. And I need to know because they want me to solve their problem, so if they want to do this one question at a time that’s fine, but if I start out going one at a time I get complained at for being too slow.

I’ve also tried everything I can think of short of being explicitly rude in my messages. Numbering them doesn’t work. Bullet-points don’t work. One question per paragraph doesn’t work. Asking them explicitly to answer all questions doesn’t work (how did these people ever pass an exam?).

(And yes I’m aware I haven’t answered all your questions (-: )