phone book ad.

Hello, our business has a full page phone book ad in our local phone book. This cost us some here around 15,000 annually just for this af alone. I personally think that it's ineffective and we could spend our advertising dollars more wisely. I have pitched the idea to the other members involved but they don't agree. Our local rep from the advertising company provides us with a list of leads and calls that said ad "generates" however I do not buy his sale pitch. I know a large portion of our customers are generated by word of mouth. I don't believe down sizing the ad or doing away with the ad all together would hurt our business at all.

What can I do to pitch this idea in a more persuasive way?