You can only block someone if they are following you first. If that's the case, go to their profile page and near the top you will see the options 'Follow' and 'Block'. Click 'Block', and that prevents them from following you, making it harder to see your Q&A history.
And if you are having problems with other users on Ask, and something they post violates the Community Guidelines, please use the 'Report as' link under the question, answer or comment in question and the moderators can look into the problem.
Unfortunaltly you can only block them if you are following them I am so sorry to hear that I know what you mean though I have seen some people be really mean to others and also to my friends and it makes me upset and I do what I can to help.
I just went through a lot of your questions. Most were about bullying. What I didn't see were any unkind remarks by the ask members. Possibly you are bullied at school. I think you need to talk to a trusted adult about your problem. I can see this bullying stuff really bothers you. I hope you can get some help. I send you heartfelt kindness. Be Strong.