When I asked AT&T why I had to go through Verizon to have our number transferred to Vonage, I received this reply:
Apparently AT&T is a CLEC (competitive local exchange carrier) wheras Verizon is our LEC (local exchange carrier). According to my reading CLECs lease network equipment from LECs and operate under somewhat different rules. (There are some good articles in Wikipedia on this.)
Anyway Vonage should have know this from the outset and not told us that it takes at least 10 to 14 business days for the number transfer, since they must have known that AT&T could not port the number to Vonage. Instead the wait cost us money and aggravation. AT&T Callvantage even states in their web site that, if the number cannot be transferred, the contract is canceled with no expense to the subscriber. We are thinking about transferring our account to Verizon and subscribe to Verizon Voicewing.