My experience was just the opposite. Maybe calling and being cordial helps, not sure but... I'm on my third motor. The first one just quit, they replaced it no charge. The second one got noisy, they also replaced it no charge. The motor's case is spot welded together no taking it apart. I'd suggest a bit of machine oil applied to the upper bearing. This one works fine. If it didn't I'd call (and be nice) and I bet I'd get another.
On all the replacements, they paid the return shipping and I had them in days.
You get a lot more flies with honey than you do with vinegar.
Each replacement came with a new fan too.