Q.Why Is My Ponytail Palm Breaking Off Its Upper Leaves?
Why is my ponytail palm breaking off its upper leaves? Should I transplant my ponytail palm? Please see photos
Certified GKH Gardening Expert
It appears that the plant may be rootbound! This can be remedied by repotting. This article will help:
https://www.gardeningknowhow.com/houseplants/ponytail-palm/how-to-move-ponytail-palms.htm
As far as what has cut the top off- That will be hard to say without catching the culprit in the act, unfortunately.
Here is an article that will help you with general care of the plant:
https://www.gardeningknowhow.com/houseplants/ponytail-palm/ponytail-palm-care.htm