dude then you should use Yetitel it is little expensive but good connection.It is run by the Two Nepal Govinda and Shantos living in Australia.It is very good in customer service,connection  , easy to call. Try out no pin need.Just like Rebtel they will give u one  numeber call any where. Every 10$ is charged when you have used a minutes for amount of 10USD .But only the things is that you cannot check how minutes u have used after making call same day or other day they will send you the invoice every end of the month. I have been using since last 5 months. O yeah there is a dallas address but it just make sure that is run form the USA. Try and let me know how it is.

Yetitel.com