Context: I am an undergrad, and working in a research group over 7 months now. I have asked my P.I (group leader) whether he would write me a recommendation letter one month before the deadline of Master's programs, and he said that he would.
Now, the deadline was yesterday, and he haven't write me any letter. I have reminded him the letter regularly via email, and he responded positively, and when I reminded him again just one day before the deadline, he said that he will write it after finishing a report, and still there is no letter.
What is the most logical course of action in this case?