What makes you think that there is a slight chance you can even be taken into consideration by chinese authorities? You are dealing with a comunist regime who participates in every aspect of local and national economy and business. The comunist party owns every company in China even bitmain which is highly profitable in every aspect of the chinese economy and energy industry.
Not even in your wildest dreams any action against bitmain will go thru using the Chinese authorities. However, in the USA there is a legal figure called "Class Suit Action" and in this particular case it perfectly fits what it was created for.
All what is needed is several of us all together to file a legal suit against bitmain in the USA for wrongful and deceiving selling practices by selling and distributing defective merchandise and offering no warranty in the USA.
Bitmain is registered in the USA as a company so if there is a substantial number of people filling for a class suit action we may, at least, receive a full refund even if some time have passed.