INDEX MATCH formula not working as expected

Good afternoon Excel experts, I am trying to use an index match formula that I have used numerous times in the past, but for some reason it is not working for this particular dataset. Can someone please take a look and tell me if I should be using an array formula? Or is that only used in calculations. Any and all guidance is appreciated on this one! See attached Example workbook.

Sheet 1 contains the data I wish to match to Sheet 2 to pull back a matching cost center. I'm also attempting to do a nested match, and the formula structure I used is what I found online that was recommended. Thanks!

Thank you very much alansidman for your response. I know how to write an index match formula. As mentioned in my post, I've used the formula numerous times before. What I need help with is WHY is it not working on this particular (attached) dataset.

And I've actually used this tutorial to figure out the multiple criteria match, but it's not working, or rather, I'm doing it wrong.

Hey thank you Trevor! That worked! I had to adjust the formula slightly, but that achieved the results I needed. Thanks so much for your expertise and guidance! Much appreciated. Cheers

Lol, I actually tried to update that earlier today, but I kept receiving an error message when I tried editing that information ?? I'll try again. Thanks again for the help!

Thank YOU for the alternative formulae, this one, =FILTER(Sheet2!$C$2:$C$31,(Sheet1!A2=Sheet2!$B$2:$B$31)*(Sheet1!C2=INT(Sheet2!$A$2:$A$31)),"not found"), worked perfectly. Much appreciated! Cheers