I had a look at those, and there some other ebay sellers that look similar to that.
I'm afraid that is probably not (I'm 99% sure) a genuine Minibox M2-ATX but a cheap chinese copy.
That is why I did not buy one from them. I got mine from LinITX, cost me more than that one, but I know it's a genuine MiniBox unit and Chris there gives great support.
Doubt you are entitled to any refund or replacement unless it is definitely faulty.
The ebay auction does list both wattages,160 and 150, so maybe that could be grounds for an Ebay dispute.