I am surprised it does not throw an error, but the [Name] field is a varchar, so you cannot insert t5tu into that field without surrounding it with single quotes…
INSERT INTO [Users] ([PinCode], [Name], [UserRole_Id]) VALUES (7777775, 't5tu', 4)
You should also practice using SSMS to see if your query is valid before trying to code it into SambaPOS. You should find that SSMS throws an error with your query, but not when you use the one I provided.