Is it true ladies should not cut their hair because it has to cover the chest on the last day?

This is completely not true. This is something which is not from Islam. If you're female, you want to cut your hair, go ahead, Bismillah, cut your hair. Okay, live your best halal hair life. No problem with that. The only thing is with female hair, you just need to ensure it's not a haircut which is specific to males. But apart from that, live your best halal hair life.