Linking data in cells among worksheets

I'm trying to create a workbook that has 3 worksheets. The goal is to pull edited information from an excel file into the workbook.

Worksheet 1: General information
Worksheet 2: Weekly updates
Worksheet 3: Monthly updates (initial load)

At the beginning of the month (i.e. the initial load). The information is pasted in WS 3. I have a Vlookup to linked to WS 1 to pull information from WS 1 to WS 3.

On WS 2, I created a index/match function to pull the information from WS 3 to WS 2. It works fine as long as the information on WS 3 matches (row/column) the information on WS 2. However, if I upload new data into WS 2 (same data, but the order changes) the index/match formula does not work.

The Vlookup is tied to a customer ID # on WS 1. The index/match is tied to a sales order #.

Am I not using the index/match correctly or is there a better function (formula) in excel to use rather than the index/match? I would like to keep this as simple as possible. would appreciate any advice to better understand this challenge.