Everyone's situation is different. I have been a vendor on here for 15 years now ( yes it says I joined the board in May 2001 but I am sure many don't remember the big "crash" of the board that year! Was on here well before that!) and don't use the phone. Been that way forever and don't plan on changing. I am a middleman for different suppliers as well as making my own cold air kits, MAF pipes, turbo protectors, fuel pressure gauge kits etc. Sure as heck don't know any vendor that doesn't sell others products.
I don't have any staff members except ME! I work a full time job where I am also on call 24/7 and then put in a few hours a night on the Buick business. If I am on the phone for an hour with a customer then I don't get my work done. A one hour conversation to answer a couple of questions that can take 30 seconds by email is a big time saver for me. And I do answer emails quickly and most can vouch for that. Receive and reply to them at my day job too, but don't tell my boss.
As far as Racetronix is concerned I had a fuel level sensor issue where it would always read past full on the gauge. I bought it used from a member on here with only "test" mileage on it. Contacted Racetronix thru their forum and received a new sender without any issues and I wasn't even the original buyer. Seemed like great service to me.