With so many Sales Leaders here, When a client say "im not interested" then continues to talk gives us business pain should we continue the conversation or end it there?

I often run into customers that say well im not interested, they don't immediately hang up on me I acknowledge they aren't interested, however in some cases they continue to talk and there tone reflects someone that may be interested. I ask I know you said you weren't interested just curious would it be ok if I ask you a couple questions? Then they start answering questions for someone that does indeed have "pain". I monetize that pain should but alot of those same customers flake, some dont. In yalls experience is it worth pursuing someone that immediately says they aren't interested. Curious about yalls thoughts on this and any advice is welcomed!