I can't Escape

I thought I had escaped my abusive ex FWB, but he keeps messaging me, at first trying to get me back, but now he's just st calling me selfish and saying I was just as bad because I "cheated" and I knew we really were together and shit and I'm crying. I don't even know why I am. I can't bring myself to block him but fuck I wish I could. I just wanna forget

Update:

I honestly have no idea why I can't block hij