Displaying A 0 Value When There Is No Count Field

Hopefully this makes sense. I am new to SQL Reporting. My code is below. I am trying to get my query to display 0 when a category (prob_ctg.sym, does not have a Count value.

SELECT COUNT(*) AS Expr2, ISNULL(COUNT(*), '0') AS Total, CONVERT(varchar(20), Requestor.c_last_name) + ', ' + CONVERT(varchar(20),
Requestor.c_first_name, 112) AS Customer, Calls.ref_num, Calls.category, prob_ctg.sym, Calls.summary, DATEADD(s, Calls.open_date - 21600,
'1/1/70 12:00:00 am') AS OpenDT, DATEADD(s, Calls.close_date - 21600, '1/1/70 12:00:00 am') AS CloseDT, [Group].c_last_name AS GroupName
FROM ctct Requestor INNER JOIN
ctct [Group] INNER JOIN
call_req Calls ON [Group].id = Calls.group_id ON Requestor.id = Calls.customer INNER JOIN
int_org INNER JOIN
prob_ctg ON int_org.id = prob_ctg.organization ON Calls.category = prob_ctg.persid
WHERE (int_org.iorg_c_id LIKE '%400111%') AND (prob_ctg.del = 0) AND (DATEADD(s, Calls.open_date - 21600, CONVERT(DATETIME, '1970-01-01 00:00:00',
102)) BETWEEN @stdt AND @eddt)
GROUP BY Calls.category, prob_ctg.sym, Calls.summary, Calls.ref_num, Calls.open_date, Calls.close_date, [Group].c_last_name, int_org.iorg_name,
int_org.iorg_c_id, Requestor.c_last_name, Requestor.c_first_name