SUMPRODUCT equation

Please I need a help

I have a different sheets from different supplier, and I want to sum the sold quantities from each supplier in a different sheet.

So the sold qty in the total sheet will be the summary from supplier 1 to supplier 4 by each day

sometimes, the items duplicated in the supplier sheet, and other times we make sort in the supplier sheet.

So if we make sort from A to Z in supplier 1 and sort from Z to A IN supplier 2. the SUM from start to end will never gives me the right results