Why does it appear that am I being billed by both Vista and PGE?

You are NOT being billed for natural gas twice. Most people do not realize that a significant portion of their monthly gas bill is a gas transportation fee. PG&E will still charge a transportation fee to those using a third party supplier. PG&E charges each customer a transportation fee in order to cover costs associated with owning and operating the pipeline. Traditionally, transportation rate represents a large portion of your monthly bill – nearly the value of your gas. The charges on your bill from Vista are for the natural gas only and are different from the PG&E transportation charges. Remember, when PGE was your natural gas provider the transmission costs were into one “bundled” charge.