SQL statement monthly payment check

I have a project about gym management and I want to check monthly payments.

For example, I want to check the last time a member paid, if the payment day was 30 days before, and if his status is active.

Here is my code, but it needs to be fixed.

SELECT * FROM (
               SELECT 
               pi.FighterID, 
               FName, 
               LName, 
               Convert(varchar(20), 
               PaymentDay,1), 
               PaymentDescr,
               PaymentAmount, 
               Active,
               ROW_NUMBER() OVER (PARTITION BY pi.FighterID ORDER BY PaymentDay DESC) rn
                        FROM 
                          FightersInfo fi LEFT JOIN 
                          PaymentInfo pi ON pi.FighterID = fi.FighterID
                        WHERE 
                           NOT EXISTS (SELECT * FROM PaymentInfo WHERE FighterID = fi.FighterID
                                                                                     AND DATEDIFF(day, PaymentDay, GETDATE()) <= 30 )
                                                                  AND Active =1) t
                                                            WHERE rn = 1

This only returns the first member. If I remove WHERE rn =1, it returns all payments. I only want the last payment of each member.