I’m not exactly sure what kind of advice you’re asking for because I don’t see a specific question in your story. However, I think what you really want to know is how to get her back, how to earn her respect again, and how to make her choose you over the guy she’s involved with on Instagram.
It’s difficult to force a woman to come back, especially if she no longer wants the relationship and someone else has already captured her attention. It’s possible that she sees something in the man she met on Instagram that she didn’t find in your relationship.
If you truly want her back, be patient with her. Try to win her over again. Show her your effort and let her see how sincere your feelings are. Give her reasons to remember what made your relationship special. Over time, if her feelings for you return, then you can ask her whether she would be willing to give your relationship another chance and rebuild what you once had together.