Compare Customer Numbers

I am auditing a CRM with monthly subscriptions. I found that some cards were saved to the wrong accounts in an integration. I have a good set of data from the payment processor and then the set from the CRM that I need to audit. There is over 12k lines here so manual is not my favorite option. I need to group like customer numbers together and then see if all of the names in that group match or have a similar word (last name). I changed the cell color of the Processors information to blue and then combined the names and ID into a list to compare that way, but I don't know how to create a report or a trigger (good or mismatch) to dwindle the list down to what I need to fix.