# Was if ($$user_hash{SERVICE}->{$service}){
# Equivalent to if (${$user_hash}{SERVICE}->{$service}){
if (exists $user_hash->{SERVICE}{$service}) {

##</code><code>##

# Was my @users = @$user_hash{SERVICE}->{$service}->{USER};
my @users = @{ $user_hash->{SERVICE}{$service}{USER} };