[Freeswitch-users] Determine if a number is valid/working

HI All, My web site customer's call center claims that 1/3 of their web leads have nonworking phone numbers. Short of calling it, is there any way with FS (or even a paid service) to determine if a given phone number is a working number? I would like to make an Ajax SOAP call to a PHP page that checks (or dials) the number and returns a status for the validity of the phone number. I have an LUA script that will call, play a short message and hang up, but the customer thinks that may take too long. Any ideas? Thanks, Sean