It's a telemarketing call. Something about a follow up call from a financial education course or something. I politely said 'thank you, but I'm not interested' and he kept asking what I meant. I said it three times, and eventually had to explain it was a common english expression meaning thank you for your time, but I'm not interested. They then said not to sign up for things and wasting their time then, and hung up on me. Spoiler alert - I didn't sign up for anything!