I cant help but agree with Buck here but if the miner was new and unopened as the seller stated and the buyer opened the unit and ran it for 5 minutes then it is the buyers problem and buyer should open a ticket with Halong to have it replaced under warranty.

Both the B52 and B29 have to be calibrated out of the box before autotune can be enabled but there is a firmware bug that the miner never completes autotune and unless you manually change it to "Factory" the miner runs in "Performance Mode" and if you have it in a cooling deficient situation I have no doubt it could burn up but that's not the sellers fault.