Welcome to bitcoin.
Sent to address I control = mine. Period.
Need chargebacks, pay with creditcards.
If an agreement for my holding someone elses coin is in place, or I am to provide some value for an investment, etc - and failed to come through, sure I should be ostracized by the community.
But to say that keeping coins that magically appeared one night on my address with absolutely no agreement in place regarding the transaction, are not mine, is laughable.
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On a side thought: Nef has not given anyone asset info / csv - how are people who do not read this thread, and who got a large payment, to know that the extra payment wasn't from dividends / sales or somesuch.