my @single = grep {keys (%{$bigList{$_}}) == 1} keys %bigList;
my @multi = grep {keys (%{$bigList{$_}}) > 1} keys %bigList;

for my $one (@single) {
    print "$one ", join ', ', sort {$a <=> $b} keys %{$bigList{$one}};
    print "\n";
}

print "\n\nClients with multiple phone numbers:\n\n";
for my $one (@multi) {
    print "$one ", join ', ', sort {$a <=> $b} keys %{$bigList{$one}};
    print "\n";
}