I have the exact same problem
2nd that. Please give us a way to get rid of them ASAP
If you play the alien space ship challenge "Laser Barrage", you can get a helmet that makes you immune to being knocked out. So ghosts pass right through you.
Myself and a friend started today also. Ghosts made the game unplayable so we refunded. Great design choice.
No more ghosts in the game anymore~~