Compare Two Lists, Find Unique (Non-Duplicate Values), Make New List with those

Hello everyone.

I've reached my wits end and have nowhere else to turn to. I've searched every internet page and can't find the answer to this, and I'm utterly convinced that there must be a way.
Please help me restore my faith in this app..

Here's the goal of this task I'm battling with:

I have two sheets.

One sheet [Mailing List] has three columns: First Name, Last Name, Email.
The second sheet [Completed Survey] has two columns: First Name, Last Name

I want to send an email to the people who have not completed the survey, meaning the people who do not appear in [Completed Survey].

So, I need a list of their names and emails, to make a new mailing list and send a reminder email to.

This seems so simple but I cannot figure it out!
And, every formula I find online either is a) unexplained or b) uses commas to separate parts of the formula, and for some reason my version of Excel separates things (for example in VLOOKUP) with a semicolon (

Another note, some of the names are written slightly differently. For example, in Mailing List, a first name may be "Joseph", but in Survey List, their name may include their middle name "Marcel", so I need to make it so those are included.

Please help / advise! I really am at a loss at how to go about this now...

Edit: I've added a sample workbook. Ideally, the new list (First Name, Last Name, Email of the non-completed survey folk would go in a new notebook, but at this point, I just want the data to go somewhere!

excellaborer_sampleworkbook.xlsx

Welcome to the forum.

There are instructions at the top of the page explaining how to attach your sample workbook.

A good sample workbook has just 10-20 rows of representative data that has been desensitised. It also has expected results mocked up, worked examples where required, relevant cells highlighted and a few explanatory notes.

This seems to work for the sample provided:
On the Mailing List sheet add a column to identify those persons that are listed on the Completed Survey sheet using: =OR(COUNTIFS('Completed Survey'!A$3:A$6,A3)>0,COUNTIFS('Completed Survey'!B$3:B$6,B3)>0)
The formula used on the Completed Survey sheet is: =IFERROR(INDEX('Mailing List'!A$3:A$9,AGGREGATE(15,6,(ROW('Mailing List'!A$3:A$9)-ROW('Mailing List'!A$2))/('Mailing List'!$D$3:$D$9=FALSE),ROWS(D$3:D3))),"")
Note that when you open the file, your system should have automatically converted commas to semi-colons as per your regional settings.
Let us know if you have any questions.