Count if two criteria match while ignoring duplicates
Solution 1:
If you just want to count the different order numbers (in column B) that are complete (column A) try this
=SUM(IF(FREQUENCY(IF(A$2:A$100="Complete",MATCH(B$2:B$100,B$2:B$100,0)),ROW(B$2:B$100)-ROW(B$2)+1),1))
confirmed with CTRL+SHIFT+ENTER
To add another condition, e.g. assuming status in A and Store Id in B as before but with Sales Reps in column C you can use this version
=SUM(IF(FREQUENCY(IF(A$2:A$100="Complete",IF(C$2:C$100="Rep1",MATCH(B$2:B$100,B$2:B$100,0))),ROW(B$2:B$100)-ROW(B$2)+1),1))
of course you can use cells to store the criteria if you wish