Bodog is run by clowns. They probably thought that kickoff was a fumble. Just show them the official NFL.com box score that shows there were no lost fumbles in the game.
In my experience, the books get confused all the time by muffed kickoffs and blocked punts and the like, and there have been times I've had to argue with books for literally hours to get wagers graded correctly, but this one is pretty clear cut since the box score will show "no lost fumbles."