I just wanted to say that I was in a sort-of similar situation - was just a crush, not a relationship - and I remember how it made me feel, anger, humiliation, sadness. I was incensed, I was outraged, I felt insulted. And I was sad, thinking that the things this girl said to me were real, but also feeling like I didn't matter to her at all when I thought I did. It hurt. And I hated being told to "move on".
What helped were a few things - for one, time. Just not talking to the person. Letting myself think about something else, even just mundane day to day life, chores, stuff like that. For me, yardwork is a good distraction. I don't have to think about anything, but can still take my mind off stuff at the same time. If the idea of not talking to them ever again is too much for you right now, you could even say, you're taking a break from talking to them, you're putting them on indefinite hiatus. After a long enough time not talking to them, you might not even feel that much of a need to talk to them anymore. Anyway, no matter how you do it, time apart takes off the sting. Continuing to talk to the person though, just keeps them in your system and re-opens the wound, prolongs the process. But once you haven't talked to them in a while you start to see them more objectively, instead of seeing what you want to see in them.
And that's the other thing. Maybe when you see them more objectively, you see some things about them that you don't really like that much after all. Maybe you always knew these things were there, but ignored them on purpose because you thought you really liked this person. But in time you might think, what did I see in them anyway? I know I did, a couple times now. Focusing on what you don't like about someone, the things you disagree with, things about them you think are stupid, ways in which you're not similar to them/can't be yourself with the person/ways they don't "get" you, is a great way to get rid of feelings of attraction for them.
You can do all this gradually too. The wound is probably still fresh, but you can take it one day at a time.