While we haven't been able to track down a copy of the Belv script, it reportedly revolves around a cell phone that comes to life after a fluke with a microwave and becomes the main character's wingman. According to TMZ, the suit also alleges that both Her and Belv involve a love interest carried around in the main character's front pocket, and both "examine the human psyche through interactions between the character and the computer."
IMDB.com has no listing for "Sachin Gadh" and only one for a "Jonathan Sender," whose sole credit was as the dialogue editor for an animated short series called Mr. Pig & Mr. Duck in 2005.
Based on TMZ's description alone, it doesn't seem as though the screenwriters have much of a case; Scarlett Johansson's sultry OS, Samantha, wasn't exactly a witty wingman. Maybe they were thinking of TED? (TMZ)