My personal view is that you must never ever be nasty, rude or insulting to a JW. And never slam the door in their fact. No matter how much you may want to!
Reason?
It will only reinforce their Watchtower fed view that all those who are not JWS are "worldly" "bad associates" and turn into nasty human beings!
Our job is to teach them, by example, that ex JWs are lovely splendid folk.
Next time they call at your door do not tell them you are an exJW - ask them all the questions that you know they cannot answer.
For example, ask them: If god is loving why does he permit wickedness - they will never be able to answer that satisfactorily without resorting to the usual WT answers. Liken god to a doctor who, whilst knowing their patient is in pain and suffering and likely to die and whilst having a meds cabinet full of curing drugs, refuses to open the cupboard. When a doctor does it is called clinical negligence and he (rightly) gets sued, struck off and in some cases imprisoned. When god does it is called....what....exactly??!! Invite them to use their own logic. Then, and only then, tell them that you are an ex JW. All the while being friendly. Encourage them not to believe everything they hear at the Kingdom Hall - urge them to question and research.
They will go down your garden path, not with a sense of righteous martydom, but with a sense of unease!
And that...my friends...is the best of way "getting" to a JW!!!!!
And it may be that will actually start them truly thinking about what they are doing!