A guy on a blind date, I told him before that we were not suitable, and he kept texting and calling, but I couldn't answer it if I didn't.

You must have told this blind date that you two were not suitable, and he kept texting, and you didn't answer your phone or return it. That's right. Because you don't like him, you can not answer his phone calls or return his text messages. You can blacklist his phone so that he won't have these troubles. He may want to use people's psychology, chase him, use his affairs and impress you with his own strength. Maybe he likes you very much, so he keeps calling you, texting you and so on. You can understand him, but when you don't want to answer, you'd better pull him out, or you can change your phone number.