I echo the others who say to continue ignoring them. However, something to think about is that your mother may continue prolonging the issue. I'd suggest the with your mom you may need to set certain boundaries, maybe after you get DFed. You may (wonderfully) never hear from those elders again, but your mom will remain in your life. It's a different situation with her.
If the harassment continues, though, you may thing to start documenting it and threat with legal actions if they do not get your refusal to talk to them. They may just want to close their case, but some people (elders included) have no respect for boundaries.