awk -F, '
NR==FNR         {A[$1] = $2
                 next
                }

$2 - A[$1]      { print $0, A[$1]+0, $2 - A[$1]
                }
$1 in A         {delete A[$1]
                }
END             {for (a in A) print a, 0, A[a], -A[a]
                }
' OFS="," file2  file1
ABC:84, 53,1553,-1500
ABC:14, 1222,0,1222
ABC:524,0, 2626,-2626