Text::Balances does not export functions into the main namespace by default. This means you have two options. First, you could ask for the function by name:

use Text::Balanced qw( extract_tagged );
# The rest of your code from above here.
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This will bring extract_tagged into your module's namespace.

Alternatively, you could fully qualify the name:

use Text::Balanced;

my $text = 'sometexthere';

($extracted, $remainder) = Text::Balanced::extract_tagged($text);
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Phil