Phone connectivity checker service

I know that thread like this does not belongs here, but i can't find any more appropriate subforum either, anyway,
I'm looking for a service where i can load up the phone numbers of my leads i get and get them verified, which means that all disconnected phones will be deleted of the list. I was searching for this online but i couldn't find anything, if anyone knows a service like this i would appreciate if you could share it with me.

I did this not that long ago - I setup vicidial on dedicated server, got myself some really cheap SIP termination, and then set it to auto-dial and flag any DC'd records. We did something in the order of 800 records/minute. Once done, just export the list and remove the flagged records - done!

I didn't do the vicidial setup myself - far too tedious. IIRC I advertised on freelancer.com and was flooded with responses... you shouldn't pay more than about $100 to set the box up, and the termination charges shouldn't run much at all - you'll only pay for those that answer instantly, ie, fax machines.

That sounds really interesting and cheap , i will definitely take a deeper look into that, thanks a lot !