You've just sat down to dinner when the phone rings.
On the other end a telemarketing person is prepared with a telescript - a guideline for a telephone conversation. Now you too have the consumers telescript and can out-question the telemarketing person until they give up the conversation.
Download and print this PDF and hang it next to the phone.
another good trick to remember is the telemarketeers own trick (trust me this used to be my job). If you ask three questions where the answer will be a 'yes' - the fourth question is more likely to get a 'yes'-reply as well.
Try this one:
Did you call me? is it (dayofweek) today? is it your job to call people? Will you stop calling me? .... .
Then hang up.