I am so sorry to hear this. I've had a family member do me that way for years and years. I just kept forgiving her even though she tried to turn all the family against me.
I kept forgiving everyone....for years, and finally this year, everyone is starting to come around. It's hard and kids can be the worse.
They probably resented something all those years you struggled to raise them and haven't gotten over it. It's too bad they don't have someone in their lives to help them see how wrong they are. Hopefully, they will wake up. I hope so for their sake as well as yours.
Anyway, I just wanted to let you know I'm sure sorry and I know how you feel. I would say from now on, just do the best you can for them but find things that mean something to you in your life. If they wake up, great. If not, at least you know you did your best and are going on to live as full a life as you can. Volunteer work is a great way to fulfill yourself.
All the best to you and Merry Christmas from a fellow GLP'er!!!
Edit: I think I'd sit down and talk to your mom. See if you can get her to tell you what's going on. Something isn't right here and she might level with you. Good luck whatever you do.