[ask] Trigger In Sqlserver Not Working, HELPP!!

i have this trigger in my database :
ALTER TRIGGER dbo.AddVoucher
   ON  dbo.User_AddVoucher
   AFTER INSERT
AS
    SET NOCOUNT ON;

DECLARE @UserId int,
    @Add_id int,
    @voucher_id char,
    @Kredit money,
    @date smalldatetime,
    @last_balance money,
    @voucher_status char

SELECT @UserId = UserId,
    @voucher_id = Voucher_ID,
    @Add_id = Add_id,
    @date = Deposit_Date   
FROM Inserted

SELECT @Kredit= Voucher_Value,
    @voucher_status = Voucher_Status
    FROM Voucher
    WHERE Voucher_ID = @voucher_id

INSERT INTO User_Balance(AddVoucher_ID, UserId, Update_Type, Update_Date)
    VALUES     (@Add_id,@UserId, 'Kredit',@date)

select @last_balance = Balance
    from User_Balance
    WHERE UserId = @UserId and Balance = (select TOP 1 Balance User_Balance where UserId = @UserId order by Update_Id DESC)

if (@voucher_status = 'active')

    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.


    -- Insert statements for trigger here
BEGIN
    update User_Balance
    set Balance = @last_balance + @Kredit
    where AddVoucher_ID = @Add_id

    update Voucher
    set Sold_Date = @date
    where Voucher_ID = @voucher_id


END

ELSE
BEGIN
    raiserror ('Voucher is not valid',0,1)
    rollback transaction
END
go 
 
the problem is the update function is not working and the if statement always put to 'FALSE'
do you think anything wrong with the code