Well, firstly, I can tell you Xbox Support (1-800-469-9269) is Toll-Free meaning that they don't charge at all to get support. I don't know where you were told you'd have to pay, but whoever said that, doesn't know what they're talking about.
Secondly, it sounds like you may not be at the right screen, if you are already registered as a silver member and you want the Gamertag on your console (I'm assuming you registered/signed into Xbox.com with that email?), then you want to do "Recover Gamertag", which can be found on the dashboard of the Xbox 360 after passing the Initial Setup (the set up that starts on a brand new xbox). What you wanna see is the dashboard (a bunch of square tabs) then do the following:
Press the big silver X button on the middle of the controller > (make sure you aren't signed in to any profiles, if you are, then at this point you will press the BLUE X button on your controller, goto Sign Out, and then hit Yes) > Click the GREEN A button after highlighting Recover Gamertag > Enter the email address and password that you say you just set up > Hit Continue/Next > Wait a moment while it downloads your profile and Voila! You now have your xbox live account on your xbox! :)