Number portability is easy: the action of porting automatically closes the account you're porting from.
Wrong! For some reasons voip companies do not consider porting out an automatic cancel of an account. Viatalks ToS specifically state a trouble ticket is required.
The act of transferring a phone number to another provider does not constitute the cancellation of an account. In the event of an outbound phone number transfer you acknowledge that it is your responsibility to contact ViaTalk LLC in the form of a customer service ticket.