Something similar happened to a guy I know. He needed a 4mm fork key, so he ordered it and got a 40mm one.
"My drill seargent helps me learn! I am just a lowly worm! My drill seargent helps me learn! I am just a lowly worm! My drill seargent helps me learn! I am just a lowly worm! My drill seargent helps me learn! I am just a lowly worm! My drill seargent helps me learn! I am just a lowly worm!"