She said she is seeing someone

we were together 6 years, and I broke it off about 10 months ago. I texted her 3 days ago and she finally responded today. Here is my problem. She seemed very very pleasant almost leading me on. I thought things were going well, and made the mistake of asking her to lunch. (that’s when she sprung it on me) her reply was she can’t because she was seeing someone. Then proceeded to tell me thank you for giving her closure and that she “truly” wishes me all the best. I didn’t say anything else, and just ended the conversation.
Question is, do I still have a chance? Do I need to start the no contact rule again? I believe her relationship is a rebound since she is still on e-harmony, and hasn’t blocked me. (BTW I have ignored her profile completely).

There’s no way to know for sure whether the guy she is seeing is a rebound or not. Cancel the lunch and contemplate why you broke it off with her and why you’re interested in getting back together. Sounds like she has moved on. Don’t stalk her social media. Do no contact if you want to, but also consider dating other women.