Use your job title so, if you were customer service put, that you were a rep. List the various tasks you did and skills you used, web use, email, multitasking, attention to detail etc. Make your skills the focus and display answering phones was simply your medium for communication.

Find a job listing that you want to apply for (or read a sample description if a job not listed) and customize that list to what is needed, demonstrate you have skills required and beyond answering a phone and reading a script.