The difficulty you are having is because check returns the ten element list of key-value pairs, not the value associated with the passed key. You'll get your expected result if you include the explicit return statement return $message{$ck}; as the last line of your sub.

As a side note, you should make sure that code you post passes perl -c (compiles). Yours does not because you didn't include a line like:

my $csv = Text::CSV->new;
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