[Lostie!]

They "made up" and fell out numerous times, the fact is they were never exactly the best of friends and Natasha never owed Jenna anything. Her only loyalty was to Farrah (I think the fact that Jenna nominated James and then moaned about being betrayed when he didn't save her and later nominated her speaks volumes about how loyalty / betrayal works in her little world).

Jenna expected loyalty from people who didn't have a reason to owe her any, in a nutshell.