Below is the latest guidance (January) I could find on the Zynga With Friends Help Site. Looks like your problem will self-resolve for you shortly. Although, I also read that auto-resign feature has burdened their servers, causing the time frame to extend at times.
From Zynga With Friends:
Contact list games automatically resign on the 12th day of no activity.
Random games automatically resign on the 6th day of no activity.
*We are working to provide the ability to 'Resign' at any time. This will be available in a future update to the game.