Jesus. I can't believe that people are falling for this.
It's so obviously fake. There is absolutely no reason that Bitmain would ever contact you directly with an unsolicited invoice asking you to pay for a heavily discounted unit, when there is absolutely no way that they were going to even identify who has paid and who hasn't (assuming that they are legit, which they are not), if payments are directly sent to a common bitcoin address.
All that needs to be done is some research and due diligence. People should look up the offer at least before sending funds to it. If there is nothing official that would suggest this offer is legit, then simply don't take the risk.
Correct! They wont tend to make or sent out unsolicited invoice just for those discounts as you have said they wont even recognized directly or easily on which buyer do able to pay or not.
With those 3 transactions on the btc address given, it seems they are fake ones same as others presumptions, this is an old scammers technique sending out some funds just for anybody to believe
that they are legit.