Don't understand. U yourself choose to engage the plumber. You want to skip paying?

But u allow him to fix the door right? He fix also by your request. If his quality bad why u keep engaging him doing other stuff? Can't blame him all u know.
All these blue collar worker or I call them handy man, u expect them to have registered company? Please la. Asking invoice from them?
under what category in income tax can u for fixing your house as and individual?

Just pay up. We can't suggest you to scam your contractor not paying him.