The only amp failure I had, which required contacting a distributor, was an all valve Mesa 400+. Westside were very good to me in sorting out that situation. Like most customers, I have never had a problem with SS or D class amps (fingers crossed).
Thanks to Agedhorse for giving us some background to the technology. Seems to me the OP hasn't been dealt with badly by the other parties in this, but is unlucky to be one of the very small percentage who has suffered a failure with this technology.