I'm going to close the door in a salesperson's face
Why would you close the door on the salesman's face?
I hate people who cannot provide what they promise
Salespeople can be pushy and not live up to their claims, you are fine to refuse them if you want to. You should never be rude though and close the door on their face. They're just trying to make a living like the rest of us.
I don't care I'm trying to buy something and the employee is being rude. I just want to close the door on their face.
If you aren't interested then try not opening the door next time they come around? Use your doors peep hole if you have one. Or just explain to them that you're not interested at least before closing the door on them.