dude, nothing wrong with the unit. sharp nukes use a type of ac motor that couldn't care less which way it is going.
this is common of older and cheaper ac motors
the idea is that the direction is determined at startup and it continue in that direction. if you hold the motor it will try to go the other way. as far as the dinner is concerned its getting the same nukeing either way and couldnt care less cause its goose is cooked either way. the only thing you should be worried about is that it spins at all.
old ac powered can openers also randomly started either way. and to force one way you'd trigger it until it went the way you wanted (only mattered if the blade was dull in one direction)
i have exclusively owned sharp nukes since i was a kid (technically i didnt own it then but you get the point), and they always randomly started in which ever direction they wanted. at least 6 units i can recall anyway.
its due to the A in AC. the guy you rang should have known this.