#!/usr/bin/perl
use strict;
use warnings;

my %sum;

while (<DATA>) {
    chomp;
    
    my ($key, $value, $reason) = split(/\|/);

    if (! defined $reason || $value !~ /^\d+$/) {
        warn qq<dropped line: "$_"\n>;
        next;
    }

    $sum{$key}{value} += $value;
    push @{$sum{$key}{reason}}, $reason;
}

local $" = '/';
for my $key (keys %sum) {
    print "$key|$sum{$key}{value}|@{$sum{$key}{reason}}\n";
}

__DATA__
USERID1|2215|Jones,Tom|
USERID1|1000|Jones, Tom|
broken line
USERID3|1495|Dole, Bob|
USERID2|2500|Francis, Pope|
USERID2|1500|Francis, Pope|

##</code><code>##

dropped line: "broken line"
USERID3|1495|Dole, Bob
USERID1|3215|Jones,Tom/Jones, Tom
USERID2|4000|Francis, Pope/Francis, Pope