Instead of insert trigger SQL

Instead of insert trigger SQL

I am trying to create an 'instead of insert trigger' that will not let the
name 'john' insert anything into a table. My problem is that even if i
change the name to something else, the query is successful but the values
arent added.
Any help would be appreciated, thanks in advance.
CREATE TRIGGER InsteadOfTrigger
ON Question4
INSTEAD OF INSERT
AS
Declare @name varchar(50)
Declare @question varchar(50)
Declare @Answer char
Set @name = 'John'
IF (select Username from inserted) = @name
BEGIN
RAISERROR ('You have not paid up your fee', 10,1)
ROLLBACK TRANSACTION
END
ELSE
BEGIN
INSERT INTO question4
values (@name, @question, @Answer)
END