Some poor sod made a mistake and would be punished for it.
Yep they certainly would.
If you can live with your conscience I guess you could keep it, but I'd be emailing/phoning the company to let them know they had screwed up and sent me something I hadn't paid for.
Yes I could live with my conscience. I have done worse.
I just wouldn't be able to enjoy having whatever it was knowing I hadn't paid for it.
I would.
FFS Send it back. otherwise you are Stealing
Nah, it's a freebie, they sent it to the OP in error, she never asked them to, she cancelled the order.
Genuine question: why the urge to keep something you never paid for?
The Op did pay for it but they refunded her. Their error, their loss.
I have said I would not and meant it. Breathtaking lack of moral compass.
Yep I have a BREATHtaking lack of moral compass. Oh the drama, it's soooooo breathtaking!! BREATHTAKING I tells ya!
You have obviously been raised without being taught the most basic of morals and I pity you.
You're probably right, but no need to pity me hun. I probably have more WAY stuff than you. Some of it I paid for, some of it I had given to me, some of it is poached, some accidentally sent to me....
I have lost stuff that has never been returned (in the past,) it's just re-addressing the universal balance.
Have a good day all. I'm just off to the coffee morning at community centre to nick a few mince pies. Save me buying so many next week. 
I'll leave you all to clean your soapboxes, and polish your halos! 