I am curious which REI you are dealing with. They bike techs here in the Bellingham REI, have taken in my bike several times to figure out and fix weird noises, do a tubeless install, a Nyon upgrade (with motor drop to run the wiring), Bosch system update and tweaking, and all I have been charged for is valves, tape & sealant, no labor charge for any of it. They got after it diligently and interfaced with both Cannondale and/or Bosch effectively to resolve my issues with the bike not having to stay overnight once. They are positive, eager to help and feel totally sincere, patient and willing to make sure I am happy with my bike's performance. Thus, your experience is totally opposite mine. It just sounds like you walked in the door with a chip on your shoulder and got what you expected. So did I. So I wonder if our different expectations was a source of the different outcome, or was it just the personnel here versus the personnel there?
Let's do that ride sometime.