It looks like you might be able to add:
Code:
ClearUserHasParachute(id)
to the end of the function RemoveUserParachute(). Then remove all uses of MarkUserHasParachute().
Then you need a way to give the parachute. I'm not sure how your shop works so you just need to create whatever it would take to be called by the shop to call MarkUserHasParachute().
This might not be the only changes required but it's a good start. You'll just need to test it. Probably test it by itself without the shop stuff and just have a command to give yourself the parachute for testing purposes.