So, I didn't quite know how to word the question so here is some clarification. People in my extended family often ask missionaries to visit me and my family, and they do, a few times a year, for a few years now despite the fact I say clearly that I am not interested in having talks or having them return to my house. Of course every time it's new missionaries so I can't get angry at them, but it's starting to get annoying...

That would be annoying. I would suggest that you do two things. First of all, talk to your family members. Tell them that you love them and respect there right to believe as they wish. Also tell them that you appreciate that their concern for you in sending the missionaries to visit. Then ask them to respect your right to believe as you wish and stop wasting the missionary's time by sending them to you. If this does not get them to stop, then go to phase two. The next time the missionaries show up at your door saying that they were referred to you by someone, explain the situation to them and then tell them to make a not in their records that your relatives keep referring them to you despite the fact that you have told them that you are not interested. Suggest that they put this someplace where succeeding missionary companionships will find it and know better than to follow up on these referrals. Hopefully, one of these two actions will stop them from coming to you so often. It probably won't stop them from knocking on your door every few years in the course of their normal canvasing of neighborhoods in your area, but hopefully it will stop them from coming around as a result of family referrals. Let me just close with this. When I was a missionary, one of the last things that I wanted to do was go back to and harass someone who had already turned down the invitation to learn about us. That sort of thing usually just gives people an impression that we are trying to force our religion on them. So, i am sorry that your family hasn't learned that lesson for themselves.

The question doesn't make much sense. Why are they being asked to visit if the person doesn't want visits in the first place?