editorNadia replied almost 2 years ago:
She's probably really embarrassed to know that you overheard her conversation. No one likes to be caught gossiping about someone else--especially when they're saying something mean. This is probably one of those situations where it's best to take the high road. When you do see her, just focus on the positive: You care about her son, you really want to have a positive relationship with her, you understand that she wants the best for her son and you hope that you can be that person for him. Make an effort to get to know her and to help her get to know you. Of course, that's really hard if she won't call you back, but if you just keep reinforcing the positive, she may eventually feel comfortable talking to you.