canceled monitored service phone line still conected?

we canceled monitored service but the signaling is still connected,i know what i have to press to turn it into a bells only do i have to do this or can i just leave it as it is,i did hear when you set and unset it may still dial up somewhere and you will get charged every time you set and unset if the signaling is still connected?????????????????? i personaly dont think this is true. thanks