I have read a couple of recent news reports to the effect that some of the big banks have been trying to get consumers to pay more than the $50 by issuing confusing instructions to the consumers, and by adopting policies that require the consumers to do things that they are not required to do according to the federal statute.
Anyway, by law, the most your liability can be is $50. Don't pay any more, and if Capital One demands more or will not issue a replacement card, file a complaint with CFPB. See links below.
Consumer Financial Protection Bureau
15 U.S. Code § 1643 - Liability of holder of credit card
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