79468 Payment Integration-2CheckOut

I am using (or trying) to use 2CheckOut as my payment provider for a membership site. I need to have 2CheckOut return control to a script on my site so I can update my datatbase and add the user to my site. 2CheckOut does return control, but I cannot read the variables it passes back. I need someone to look into this for me. This should be one hour or less for anyone who has worked with 2CheckOut before.