Sumproduct Column Criteria

Hello everyone.

I have data I would like to sum, with the days on the first column and the first row goes like: January Sales, January Tests; February Sales, February Tests and so on for the rest of the months.

Where I'm placing the formula, I have as header "month 1 sales", "month 1 tests", "month 2 sales" and "month 2 tests", and 2 rows indicating the month 1 and month 2 through data validation. The idea is to sum the column where the information is found.

Although I'm able to "match" the criteria (when I evaluate formula, I only get 1 in the desired column), I'm not able to make it sum.

Here's the formula I've tried:

HTML Code: 

I'm not 100% sure that sumproduct is the right formula to use, so as long as the formula fits my needs, feel free to suggest.

Thank you

Yes, after entering the tag, i've searched it and some people had the same problem.

Should've remembered it sooner.

Ended up with this formula:

HTML Code: 

Thank you for the quick replies anyway.

Please feel free to delete the thread if wanted.