I am trying to pull data from one file to another.

For simplicity, my data includes multiple customers and multiple products:

Cust. group #/ Cust. Name / Product code / Quantity
001 / Bob / A / 10
001 / Bob / B / 5
001 / Bob / C / 20
001 / Ted / A / 35
001 / Ted / B / 30
001 / Ted / C / 15

I need to look up using a customer group number (contains multiple customers
belonging to one group), and also look up by product code, to provide the
total quantity of that product.

I am using the SUMIF function but for some reason it is returning only one
figure for everything.

There is another trick to this equation, I need to separate this by weeks
(ie. week 1, and week 2 --though I can separate this into separate worksheets
for simplicity - but an extra step).

Thank you.