Look at this line:

@redi = $responsetextall[$i][$j]{set}{Client}{redirect_uris}
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What does $responsetextall[$i][$j]{set}{Client}{redirect_uris} contain? Does it contain an array reference? You are assigning that array reference to @redi so that @redi contains:

@redi = (
    [....],
);
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It contains a single element. That element is a reference to an array. You should have done one of two things. Either this:

@redi = @{$responsetextall[$i][$j]{set}{Client}{redirect_uris}}
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...or this:

$redi = $responsetextall[$i][$j]{set}{Client}{redirect_uris}
# and then...
for my $i (0..$#$redi) {
    $worksheet->write($r, 6, [$redi->[$i]]);
}
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The first one is an easier change, the second one is a little more memory efficient.

See perlreftut, and perllol, perhaps.