When I sold shoes we had the same problem with shoe brand Saucony. Customers would ask for Sock-nee, Sau-cony is the correct way to pronounce the brand . I use to ski on Dynafit skis the shop owner called them Dana-fit then the Dynafit sale rep friend of mind called them Dyna-fit .
Pronunciation of brand names I feel their is no correct way the individual says it long as they get their point across. Being in Sales most of life I have seen sales people and sales reps against sales reps having great useless debates over how a brand name is pronounced.
I have also seen snobbish sales people constantly correcting customer on the brand names they are asking for and making the customer feel inferior for mispronunciation of the product, Instead of just getting them product.