Telephone Book to the Masses

If you need a number, call me. No, pick up a phone book, look online, or call 411. I don't mind giving numbers out. Don't get me wrong, but I have had an interesting year of requests. I have had co-workers requesting me to contact their boss or other personnel because they couldn't ask what they were suppose to be doing on a training day. I try to help people out, but now it feels like it's an expectation and no gratitude. First off it is not my job to make your phone calls. I don't have all the answers and have never claimed. I usually doubt myself even when I do know an answer. So why? why? do people have the feeling that when I say, "I can give you the number." Their response is "NO, I can't do it. You need to call." I really need to learn the art of saying "No.". Instead, I find myself making phone calls for other people. Is it ever appropriate to hang up a phone on someone if they don't get the fact that you are saying "NO?" Am I being unreasonable?