Not paid for unused vacation days after leaving old firm

So I left my old ib job for a competitor a few weeks ago. When I submitted my 2 week resignation, my boss asked if I was planning on burning some of my vacation days in those two weeks or I would prefer to be paid out for them, which is firm policy. Due to covid, can’t travel, and a need to train a new coworker brought on as a first year about a month prior to my resignation, I chose to work my last two weeks. I did not receive pay for my unused vacation days in my last paycheck. This comes out to roughly $2k. How do I go about recouping those funds? Left on good terms fwiw.