telemarketers

I am above average nice to telemarketers, and frankly I am beginning to wonder why, since 99% of the time they are rude to me in return. First of all, it isn't my idea for some stranger to call my house and ask me for money to support causes I've never heard of before. Here I am in my own home answering a phone that I suspect might be my husband, grandmother, friend calling...and instead my hello is greeted by that tell-tale second of silence. The silence it takes for the telemarketer to realize they have a live one on line, then to click over and go into their breathless spiel. Now here is where I divide between two nice approaches- each of which I do about 50% of the time. I either interrupt them right away to explain I don't give money over the phone, thus saving them from their endless rant. This is a great favor in my opinion since it saves them the time of spilling all the details when I already know in advance there is no possible way I am going to do what they want. How is this favor returned, you might ask? By them hanging up abruptly in my face. Now, I COULD have done that to them, but instead I was nice and that's the thanks I get. No "thanks anyway", or "have a good day." Hanging up in people's faces is not my way of doing things, and certainly reaffirms my initial decision of not giving them money. My second response is to let them give their entire speech, since there really is no pause in which to interject anything and I hate to interrupt. After they come up for air, I politely decline. Now this has gotten me all kinds of things in return ranging from the afore-mentioned hang up in my face to disbelief, to outright anger. My "no" is usually met with more information, as if my first "no" could not be my true feelings if only I understood a little bit more. Sometimes I start wondering if these people understand English. So often the feeling is conveyed that I have done them a great disservice, when I am the one that has been interrupted and barraged with the never ending, never pausing for breath plea for money. I haven't found a satisfactory way of dealing with this since I don't want to hang up rudely, or invest in caller ID. Any clever ideas?