What Part of NO Don't You Understand?

There is an office furniture salesman (we'll call him Lem) who has come around my office probably 15 times over the past two years. Every time, he's asked for me. Because of the vagaries of the fact that I have a job that keeps me pretty busy, I've never been able to meet with him. Every time that he's come, I've asked our secretary to tell him to give me a call or send me an email and I would be happy to set up an appointment to meet with him. He never has done that. Instead, like some sort of crazy person, he insists on stopping by again and again and again.
It finally got to the tipping point with Lem this past week. He stopped by Monday and I gave him the same spiel that I have every other time...I'm busy, call and I'll be happy to get an appointment with you (through the secretary, of course). So he finally did call, but I didn't listen to his message until he had already stopped by the day after he called. Then, he stopped by again that afternoon. Never have we talked or have I set up a time to talk with him. I'd still set something up with him, but it would be to ask him the following questions:
1. Do you really think that somehow this time is going to be different when the prior 15 times haven't been?
2. Do you think I'm actually going to buy anything from you when you don't care to listen to me when I tell you call for an appointment? It's not like you could have forgotten that, what with me telling you it over and over and over again. Write it on the business card that you picked up - "call for appointment." It's not hard to make a good first impression, but you've failed miserably before I've even met you.
3. What salesman school did you go to where they told you to keep stopping by and ignoring the customer's wishes?
4. Do you like wasting your time going someplace without that appointment when you could take a few minutes to call and then go over at the appointed time? I think that if you added up all the wasted time from stopping by and getting rejected over the past 2 years you could probably have seen a baseball game by now. It's certainly the cheaper option, what with gas prices being what they are.
5. Are you indeed mental, or do you just seem that way?