opt out phone system

aonefun

We manage our own fax broadcast campaign and are wondering if there is a phone system / service that would enable cusotmers that wish to opt out of our campaign to call up and enter their phone numbers for removal. The phone number entered would then be added to our (online) database. This would prevent the need for customers that do not wish to email us a removal request to process the request via a phone method while avoiding the need to speak with a live representative.