During the penultimate semester of my undergrad studies, I had approached a professor with a research idea, which he approved and both of us started working on it. We made substantial progress, but not enough to write a paper.
Later, I made a big mistake. I got really busy with grad school applications, job interviews and completing my graduation requirements. The later was notoriously hard because I had backlogs due to covid-related disruptions. This led to slow progress in the research arena.
The professor became really angry that I wasn't working enough with research, but I was too busy to do anything. When I communicated, he just said that I should value research more than coursework. After this, he stopped replying to my emails and told me he no longer wanted to work with me.
Once I graduated and started with grad school (in a different country), I finished the research work and wrote a paper. I want to submit this paper now. However, the professor had substantial contribution in the work so he should be an author. When I communicated with him again, he just reiterated that he didn't want to work with me.
What can be done in such a case? Would it be advisable to submit the work under my own name; or resume the project with another professor?