update: looks like it's working now
i retested sending rext out from gv, to the gv phone number (like self sending/recieving, just like you would test email account by sending an email to your own account), it worked. earlier i was to buy credit for my account in voipdiscount and they sent text to verify me, but it has never arrived. so i was thinking gv not receiving text. looks like voipdiscount has problem.. thanks everyone.