I've been using Garmin stuff since before 2005. I've always had a good result with their support.
My preference is to call them, because then I can quickly eliminate all the things I've already tried that are naturally the things they recommend first. With their phone system, they give you the option to have them call you back so you don't have to sit on hold for a long time. Usually they call back within an hour though it has occasionally been longer.
Glad you had enough gumption to fire back another email when the first didn't help. Many don't then they gripe.