The politicians don’t personally do it. You won’t talk to the actual rep, you’ll talk to some recent poli-sci grad or intern or whatever.

I suppose some might be so incredibly bad at their job that they don’t have staff for constituent services, but most do. They don’t tend to ask who you voted for before helping. I’m in a very red state, vote for democrats, and have had state and federal republican rep offices help me out several times.