I have been trying to sort large lists of data using various formulas but to
no avail.

The problem I have is my worksheets consist of approx 50 columns for
products and 365 rows for the days of the year for each client.

Because ordering patterns are not the same, I want to see when the last time
a client had ordered:
Example 1: Product no1, product no2 with product no18
Example 2: Product no3, product no10 with product no20

The problem I have encountered is that what ever formula I try, it always
returns the last day the product was ordered not when it was last order with
say product 1 and 2.