seventh day Adventist doorknockers.

I regularly get seventh day Adventist door knockers coming to my house. I don't mind I actually enjoy having a chat and agree with much of what they have to say and what is in their handouts. My issue is that I feel kind of guilty, like as if I am leading them on r something - because I am catholic, and I know I will never be swayed from my religion for another. Although I don't have a great record of actual church attendance, I am firm in my faith.
I am not sure if I should be saying something to the people when they door knock (they aren't always the same people), or what?
Am I just wasting their time and leading them on?

I am unsure, because as a catholic I was brought up to talk about religion with people of all denominations, but there was never ever the view that we should try and convert anyone (but rather look for the similarities between the religions and focus on those rather then our differences). I understand that 7th day Adventist have a different view to this, and I don't want to be wasting their time or resources giving them a false belief that I might convert or whatever.
I'm not sure if this even makes any sense. I enjoy the chats and discussion, but come away feeling I have somehow been misleading or untruthful, and I don't like that feeling.

I had a similar issue with our local JWs in Perth.
Really lovely guy and he would come around with his now wife and other family, etc. and we had great conversations and they would come around every time they were in the area.
But I really wanted to make sure that while I enjoy theosophical discussion and am always keen for that, that any attempts or thoughts they had about conversion were going to be nothing more as a waste of their time, as I am quite happy and fulfilled as pagan. There was also conversation that given what 'they' (the JW teachings) think bout paganism and what I beleive, then perhaps they would be more comfortable leaving and not returning.
They chose to respect my faith it was great. Really nice and lovely people, happy to ask questions and hear the answer too not just try and preach at me.

So I think definitely be honest - but leave no room for ambiguity on how steadfastly you are set in your faith - and if they then choose to come back, that will be your answer. :)

I enjoy the conversations too - at times - but it's often an inconvenience. What I do now is I start the conversation by saying "are you witnessing today?" and when they say yes, I thank them nicely for wanting to share their message but no thank you. It's always polite but they move on pretty quickly. I have tested the same "call control" measures on sales people too - if you get in and ask the questions, they have to answer to be polite, you then get to say the next think that steers the conversation where you want it to go. Lol