If customer service and support are important, try Vig. They’re a small, boutique online scooter shop that sells well-known scooters under their own brand (usually tweaking them in the process by adding things like turn signals or more robust charge port covers), and they are very focused on support. They’re small enough to actually care so the phone is answered by a human, they offer instant chat on the website, and respond to emails usually within a couple hours (even on weekends). You almost always talk to the owners, and they’re friendly and helpful. Plus, they stock parts for everything they carry.
Oh, and they also offer a good warranty which actually seems better than anything else I’ve seen because it actually covers the entire scooter, front to back, top to bottom…not just a few select components (seriously—take a look at the warranty policy from your scooter!)
I know the owner (met him after buying my scooter from them) and he’s a good guy.