SQL custom return value based on condition

Question

I am new to SQL server, can you please help me with the query below query : I have below Table - Table1 :

 

PostingDate   ReturnCheckReason  PaymentStatus  PolicyNumber

7/23/2020    Cancel Payment                     Return            1234

8/6/2020      Cancel Payment                     Return            1234

 

Here I would to display return response as, this is customized response

PostingDate     ReturnCheckReason    PaymentStatus                      PolicyNumber

null                   Cancel Payment        ALL Payments are Canceled       1234

 

Input to my stored Proc is PolicyNumber e.g 1234 which return 5 rows

Here I need to cover below cases :-

1) If the first payment is not cancelled , I need to return that row.

2) If all the payments are cancelled for that policy as shown above, then we need to display customized message , or else my query will display NULL 

 

I have same table with below Data , then I need to handle Case 1 as shown above.

PostingDate    ReturnCheckReason       PaymentStatus       PolicyNumber

7/23/2020                    Null                          Payment                  1234

8/6/2020                       Null                         Payment                 1234

8/5/2020                   Cancel Payment           Return                   1234

 

This is my Query :-

SELECT TOP 1 [PolicyNumber], [PostingDate], [PaymentStatus] FROM [dbo].[Bil_PaymentSearch] WITH (NOLOCK) WHERE (PolicyNumber = @PolicyNumber) AND (REturnCheckreason <> 'Cancel payment') AND (PaymentOrReturn <> 'Return') ORDER BY PostingDate ASC

My query handles first case , but it will not handle 2nd case, it will display as NULL, please help me