yes, if they want to continue doing business, they should address quality issues head on...
and most important, these issues needs to be addressed at their expense,
not at the buyer's', any scrupulous seller will do this, it goes without saying...
as early as two years ago i have pointed out design flaws but the sellers
seem disinterested, after all a broken Sakura amp opens up opportunities
for others to make money at the expense of end users....