Manufacturers with great customer service

Robert Adam with Classe was GREAT when Classe was an independent entity.  Not sure what Robert is doing now a day.  I miss him and wish him well.

Octave used to be very friendly and responsive, but no longer the case since it becomes busier.

Linear Tube Audio (LTA) provides excellent customer service. 

Arcam.  Always a live person who is switched on to the product. If emailed you may even get a reply from an engineer.  
PS Audio has always provided detailed responses.  
Cardas and Kimber Kabel are solid as well.  

Hagerman Labs. I had a hum issue while using my Cornet III phonostage. My email to customer service was the start of a 10 message thread with Jim Hagerman himself. He was very friendly and helpful. He stayed with me until we solved my problem, which was a bad tube. The unit has worked perfectly in the years since.

Pass Labs, EMM Labs/Meitner, Audio Research, Bryston. All have provided me excellent customer service for both new and used components.