Seeking strength and guidance through a difficult trial

Assalamu alaikum everyone, I've never felt this isolated before. Alhamdulillah, I have family and friends, but someone is causing me immense distress. This person, who is not well, constantly harasses me, bothers my friends and my potential spouse, and spreads terrible lies. They come from a powerful family where I live, and the authorities haven't been able to help. This individual has had feelings for me for a long time and wrongly believes that tormenting me will bring us together. But the truth is, I cannot bear them. They have abused, blackmailed, and threatened me, and I feel completely trapped. I've been making du'a every day, praying Tahajjud, doing dhikr, asking Allah SWT to remove this attachment from their heart and to remove them from my life in a peaceful way, but the situation persists. My nerves are shattered; I'm in a constant state of anxiety and fear, and I feel utterly depleted. I want to move forward with my marriage plans, but they are threatening to ruin it if I don't accept them back into my life as a friend, claiming to have information from my past before I embraced the deen properly. Please, can anyone offer some advice? I am so exhausted and don't know how to continue. The thought of giving up crosses my mind, but I hold firm to the knowledge that such an act is haram-it's the only thing anchoring me right now. I ask Allah for sabr and a way out.