Every time I quit Jetpack Joyride and start it up again, I have 2659 or so coins, even if I had 20 000 when I quit playing. Is there a way to make this not happen?
This appears to be a bug with the game. According to this forum post, this issue only occurs if you quit and then start the game again in a short period of time. Try waiting a longer period of time, such as 10-15 minutes, as the post recommends.