Oh man, that's a tough call, I kinda see both sides on the re-stocking fee... only reason I feel the restocking fee is appropriate is for them to recover the initial expense of the free shipping they offer, but yeah, bumping up from 10% to 20% is kinda strange so I totally feel your frustration there. I would personally chock it up to losing more than the 20% fee if I tried to re-sell the motor elsewhere. I'm thinking RCJuice is probably a step above Integy in that at least you can get someone from RCJuice to respond, even if it takes a few days. I've had 2 times where I had to open a dispute through PayPal to get resolution with Integy where in both cases it was Integy's fault for sending the wrong item or had missing parts. I guess it comes with the territory when you try to save some cash with a budget distributor, then there are sacrifices that are made to customer service <shrug>. As far as their HobbyStar (Rocket) branded electronics go, I've been pleased with their quality, unfortunately they don't offer a 540 4-pole any higher than 3300KV through RC Juice, however I did spot a 3900KV motor here which I believe is from the same OEM:
https://www.banggood.com/Rocker-540-...p-1349664.html

That's going to be the motor I plan to try next if the Novak NX4-3900KV starts to give me any problems.